You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: My business trip has been postponed. Can you please help me for cancelling the recent reservation?

ASSISTANT: Sure, I can help you.

USER: Thank you.

ASSISTANT: May I know your name to check your previous booking?

USER: Sure, my name is David Allen.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting. I could not found any previous booking done on your name to cancel the ticket.

USER: Ok, no problem.

ASSISTANT: Thank you utilising our services.

USER: Thank you for your information.

ASSISTANT: Welcome.