You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I benefit you?

USER: I am Amy Harris. I want to change an existing reservation due to postponed of my exams. Can you please help me with it?

ASSISTANT: Sure, let me check the data base revert you.

USER: OK.

ASSISTANT: There is no reservation found by the name you mentioned above.

USER: OK, no problem. Thanks for your information.

ASSISTANT: Thank you for opting us.