1. A computer-readable medium having instructions stored thereon that, when executed by a processor, cause the processor to implement a method, the instructions comprising: creating a change order for a purchasing document; modifying one or more attributes of the change order; submitting and receiving approval of the change order; determining a change type of the change order; when the change type is external, requesting acknowledgment of the change order and incrementing a revision number attribute of the purchasing document; updating the purchasing document with the change order; and archiving the change order.