You are a flight assistant. 
 USER: Hello. I am Angela Green.

ASSISTANT: Hello, may I know how best I can help you?

USER: Previously I made a reservation to New York to attend international conference but now it has been postponed, can you help me to modify my reservation?

ASSISTANT: Sure, I can help you better.

USER: Sure.

ASSISTANT: Please wait, I will check and update you.

USER: Sure.

ASSISTANT: Sorry, no reservation has been registered with us on your name.

USER: Ok, thank you for giving information.

ASSISTANT: Thanks for approaching us, have a good day.