You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I want to change my existing reservation, because of sudden postpone of my physics exam.

ASSISTANT: Ok, I am here to help you. May I know your good name please?

USER: Sure, I'm Nicole Garcia.

ASSISTANT: There is no reservation found as per your details.

USER: Ok, fine.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your kind information.