You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Helen Phillips.

ASSISTANT: Yes Helen Phillips, may I know your concern?

USER: My business meeting has been postponed. So, I would like to take change my reservation. Can you help me?

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Ok, there is a no reservation found as you had did was not confirmed.

USER: That's ok, thank you.

ASSISTANT: Thank you for choosing our agency.