You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I made a reservation earlier to sign a contract for new project, due to some problems it has been postponed. Can you help me in changing my existing reservation?

ASSISTANT: Sure, may I know your good name please?

USER: I am Michael Lee.

ASSISTANT: Thanks for providing your name,  please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, no reservation found with your name to change.

USER: That's fine. Thank you for your kind information.

ASSISTANT: Thanks for opting us, have a nice day.