You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

USER: I am Robert White, I want to change my reservation as my tip to New York for vacation is postponed. Can you change my reservation?

ASSISTANT: Please wait a while.

USER: Sure.

ASSISTANT: Thanks for your time. We didnt found any reservation by this name.

USER: Ok, thanks for the information.

ASSISTANT: Thank you.