You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hi. How can I help you?

USER: I'm Carolyn Campbell.

ASSISTANT: Mr Carolyn Campbell, may I help you?

USER: I want to go on a vacation, but unfortunately the trip got postponed.can you please change my existing reservation?

ASSISTANT: Sure, just a second please.

USER: OK.

ASSISTANT: I am sorry, Mr Carolyn Campbell I cannot find any reservation on your name.

USER: OK, that's not a problem.

ASSISTANT: Thank you, have a nice day.

USER: Thank you for your help.