You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I am Nicholas Harris. I would like to change my recent reservation because my trip dates are postponed, can you help me?

ASSISTANT: Sure, we are happy to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: It's ok, not a problem.

ASSISTANT: Thank you for communicating with us.