You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how could I support you?

USER: I am Cynthia Carter and I want to change an existing reservation due to my exams got postponed.

ASSISTANT: Please wait a moment. May I have your name please?

USER: I already mentioned above.

ASSISTANT: Ok. Sorry to notify you that there is no reservation found on your name.

USER: Ok, thanks for your help.

ASSISTANT: Thank you for choosing us.