You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your good name?

USER: I am Elizabeth Adams.

ASSISTANT: How may I aid you?

USER: My sister marriage got postpone, Can you change my existing reservation?

ASSISTANT: Sure, please wait for a while I will check and revert you.

USER: Ok.

ASSISTANT: Thanks for waiting. Sorry there is no reservation found on your name.

USER: No problem, Thanks for the information.

ASSISTANT: Thank you for choosing us, have a good day.