the present invention is a system , method , and computer product that provides several advantages over traditional e - mail address management systems by solving problems of the traditional systems . one of the advantages provided is that a change in a reviewer may be made to a single record , without having to update each individual traveler &# 39 ; s profile . also , as many reviewers as desired may be associated with a traveler &# 39 ; s profile . another advantage is a reduction in database maintenance costs . further , any member of a group of reviewers is able to review incurrence of travel expenses by a traveler . while specific examples and configurations are described , it should be understood that this is done for illustrative purposes only . other implementations may be used without departing from the spirit and scope of the present invention . this invention may be employed in a variety of other applications . references in the specification to “ one embodiment ,” “ an embodiment ,” “ an example embodiment ,” etc ., indicate that the embodiment described may include a particular feature , structure , or characteristic , but every embodiment may not necessarily include the particular feature , structure , or characteristic . moreover , such phrases are not necessarily referring to the same embodiment . further , when a particular feature , structure , or characteristic is described in an embodiment , that feature , structure , or characteristic may be effected with other embodiments of the invention whether or not explicitly described . the invention is now described with reference to the figures . fig1 a is a high - level flow diagram that illustrates a method 100 for initializing an e - mail address management system . in step 102 , a list of reviewers e - mail addresses is received . the list may be received from a client . in some instances , a reviewer is a person , group of people , or some other entity whose approval may be required for travel . as used herein , the term “ reviewer ” also includes a person , group of people , or other entity who is provided with notification of the travel but whose approval may not be required . the system and method disclosed herein can accommodate both reviewers who merely review and reviewers whose authorization is required . a reviewer whose authorization is required is also called an “ authorizer .” in step 104 , the reviewers e - mail addresses are grouped into a reviewer group and / or a level . in step 106 , an identifier is assigned to the reviewer group and / or the level . in step 108 , a rule to leverage the reviewer group and / or the level is created . in step 110 , the identifier is added to a traveler &# 39 ; s profile . the method 100 for initializing the e - mail address management system may further validate each reviewer group prior to production use . a rule that defines requirements for a multi - level approval may be created . for example , a rule can define a requirement for escalation from a first level to a second level . fig1 b is a high - level flow diagram that illustrates another method for initializing the e - mail address management system . in step 151 , a client provides their list ( s ) of reviewers e - mail addresses to a travel - related service company , such as american express travel related services company , inc . ( amex ). in step 152 , the travel - related service company consults with the client to ensure complete understanding of the client &# 39 ; s reviewer structure to create a proper segmentation of the reviewer groups . in step 153 , each reviewer group is created either manually or automatically via a data feed . each reviewer group is assigned a unique identifier ( id ) in the e - mail address management system . the id may be , for example , any combination of alphanumeric characters . in step 154 , rules are created on a logic module of the e - mail address management system to leverage the reviewer groups . in step 155 , rules are created to define any requirements for multi - level notifications / approvals . the rules may define , for example , requirements for escalation from a first level to a second level . in step 156 , each reviewer group is validated . each reviewer group is tested prior to production use . multiple reviewers may be required in this flow . a single reviewer may take the place of multiple reviewers . fig2 is an exemplary structure for a group of reviewers having the multi - level approval structure 250 . five levels are shown in this example . level one is the highest level of reviewers . level five is the lowest level of reviewers . the levels may prevent a reviewer from reviewing / authorizing travel for travelers who are outside of a population of travelers for which the reviewer is empowered to authorize . the multi - level approval structure has at least two levels of reviewers . the number of levels and structure of groups is flexible and may be implemented to meet specific needs of a client . each level may consist of a primary reviewer , a backup reviewer , and / or an alternate reviewer . the reviewer is not limited to a single group or level . the reviewer may be a member of multiple groups . the reviewer may be a member of multiple levels . each level and / or group of reviewers is assigned an identifier ( id ) that is unique . multiple groups may be used to acquire multi - level notifications / approvals . the e - mail address management tool may provide for escalation of notifications / approvals , for example , across multiple groups or multiple levels . the client may access the e - mail address management tool to change reviewer ( s ) e - mail addresses , levels , and groups . clients may upload data files to update the reviewer ( s ), levels , and groups . a graphical user interface may be provided so that a client may manage reviewer ( s ) e - mail addresses , levels , and groups . updates to reviewer ( s ) e - mail addresses , levels , and groups may be available to all reservations immediately . fig3 a is a high - level flow diagram that illustrates a method 300 for providing e - mail address management . in step 302 , a reservation request is received at , for example , the travel - related services company such as amex . in step 304 , the traveler profile is retrieved based on the reservation request . the traveler profile has a reviewer group identifier . in step 306 , a reservation is created . the reservation includes the reviewer group identifier . in step 308 , a reviewer e - mail address is determined from the reviewer group identifier . in step 310 , the reservation is sent to the reviewer e - mail address . in step 312 , a review result may be received from the reviewer e - mail address . the review result may be an approval or a declination . if the review result is an approval , a ticket is issued . if the review result is a declination , a travel counselor may be notified . a declined notice may be sent via electronic mail . the traveler may change the reservation request . the method for providing e - mail address management 300 may further determine if escalation is required . escalation is a process where at least two levels of review and / or authorization are required to determine if the reservation is to be approved , changed , or declined . if escalation is required , a second reviewer group is determined from the reviewer group identifier . the reservation is sent via e - mail to a second reviewer in the second reviewer group . an authorization decision result is received from the second reviewer . the second reviewer group may be in a higher level in the multi - level approval structure than the first reviewer group . fig3 b is a high - level flow diagram that illustrates a method 350 of production operation of an embodiment of the invention . in step 351 , the traveler calls the travel counselor to make the reservation . alternatively , the traveler may book the reservation online . in step 352 , the traveler &# 39 ; s profile containing the id for the reviewer group is used to create the reservation . the id is in the traveler &# 39 ; s profile . alternately , another identifying code may be used in place of the id . in step 353 , authorization logic uses the id to refer to the proper reviewer group . the authorization logic sends a notice to the email addresses of the reviewer ( s ) within that group . the authorization logic is part of the e - mail address management tool . in step 354 , the reviewer ( s ) evaluates the reservation . the reviewer ( s ) either approve or decline the trip . in step 355 , approved reservations are processed . in step 356 , declined reservations held until fixed or cancelled . in step 357 , the traveler is advised of the status of the reservation as approved or declined . in step 358 , in cases where escalation of the approval process is required , other reviewer groups determine the additional reviewer ( s ) who are notified . fig4 a and 4b are flow diagrams illustrating a method 400 of high - level system flow of production operation of an embodiment of the invention . any part or step of the present invention may be implemented using hardware , software or a combination thereof and may be implemented in a computer system or other processing system . fig5 illustrates that the invention is directed toward a computer system 500 capable of carrying out the functions described herein . the computer system 500 includes a processor 504 . the processor 504 is connected to a communication infrastructure 506 ( e . g ., a communications bus or network ). various software embodiments are described in terms of this exemplary computer system . other computer systems and / or architectures may be used to implement the e - mail address management tool . the computer system 500 can include a display interface 502 that forwards graphics , text , and other data from the communication infrastructure 506 ( or from a frame buffer not shown ) for display on the display unit 530 . the computer system 500 also includes a main memory 508 . the computer system 500 may also include a secondary memory 510 . the secondary memory 510 may include , for example , a hard disk drive 512 and / or a removable storage drive 514 , representing a floppy disk drive , a magnetic tape drive , an optical disk drive , etc . the removable storage drive 514 reads from and / or writes to a removable storage unit 518 . removable storage unit 518 may be a floppy disk , magnetic tape , optical disk , etc . which is read by and written to by removable storage drive 514 . the removable storage unit 518 includes a computer usable storage medium having stored therein computer software and / or data . in alternative embodiments , secondary memory 510 may include other similar devices for allowing computer programs or other instructions to be loaded into computer system 500 . such devices may include , for example , the removable storage unit 518 and an interface 520 . examples of the removable storage unit 518 and the interface 520 may include a program cartridge and a cartridge interface ( such as that found in video game devices ), a removable memory chip ( such as an erasable programmable read only memory ( eprom ), or programmable read only memory ( prom )) and associated socket , and the like . the interface 520 transfers software and data from the removable storage unit 518 to the computer system 500 . the computer system 500 may also include a communication interface 524 . the communication interface 524 allows software and data to be transferred between computer system 500 and external devices . examples of the communication interface 524 may include a modem , a network interface ( such as an ethernet card ), a communications port , a personal computer memory card international association ( pcmcia ) slot and card , etc . software and data transferred via the communication interface 524 are in the form of signals 528 which may be electronic , electromagnetic , optical or other signals capable of being received by the communication interface 524 . the signals 528 are provided to communications interface 524 via a channel 526 . the channel 526 carries the signals 528 and may be implemented using wire , fiber optics , a telephone line , a cellular link , a radio frequency ( rf ) link , and the like . the terms “ computer program medium ,” “ computer usable medium ,” and “ computer - readable medium ” are used interchangeably to refer to media such as removable storage drive 514 and the hard disk drive 512 . the computer program products provide instructions to the computer system 500 . the invention is directed to such computer program products . a computer program , also referred to as computer control logic , is stored in the main memory 508 and / or the secondary memory 510 . the computer program may also be received via the communication interface 524 . the computer program enables the computer system 500 to perform the features of the present invention . the computer program enables the processor 504 to perform the features of the present invention . accordingly , the computer program is a controller of the computer system 500 . in an embodiment where the invention is implemented using software , the software may be stored in the computer program product and loaded into the computer system 500 using the removable storage drive 514 , the hard drive 512 or the communication interface 524 . the control logic ( software ), when executed by the processor 504 , causes the processor 504 to perform the functions of the invention as described herein . the invention may be implemented primarily in hardware using , for example , hardware components such as application specific integrated circuits ( asics ). the invention may be implemented using a combination of both hardware and software . while various embodiments of the present invention have been described above , they have been presented by way of example , and not limitation . various changes in form and detail may be made without departing from the spirit and scope of the present invention . thus , the present invention should not be limited by any of the above described exemplary embodiments . the present invention should be defined only in accordance with the following claims and their equivalents . in addition , the figures , which highlight the functionality and advantages of the present invention , are presented only as examples . the architecture of the present invention is sufficiently flexible and configurable that it may be utilized in ways other than those shown in the figures .