You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I need some help in changing my previous flight ticket booking, can you please assist me with that one?

ASSISTANT: May I know your name?

USER: Thank you for your positive response and my name is Margaret Garcia.

ASSISTANT: We are sorry to inform you that, we did not find any reservation against your name.

USER: Ok, no problem. Thank you for your help.

ASSISTANT: Thank you.

USER: Welcome.