You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I would like to change my recent reservation because my trip dates are postponed, can you help me?

ASSISTANT: Sure, may I know your name please?

USER: I am Christopher Mitchell.

ASSISTANT: Sorry, there is no active reservation on your name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.