customer: Hello. 
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 customer: I want to change my existing reservation, as my exams have postponed suddenly. Can you please help me? 
 agent: Sure, can you please provide the name on which your reservation has been confirmed? 
 customer: Gregory Martin. 
 agent: Sorry, there is no reservation found by your name. 
 customer: Ok, no problem. Thank you for your information. 
 agent: Thank you and have a nice day.
agent: Hello. How can I help you?