You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Gregory Smith.

ASSISTANT: How can I assist you today?

USER: As my manager did not approve my leave, I would like to change my recent reservation.

ASSISTANT: Sure, will you please give me a moment?

USER: Sure, take your time.

ASSISTANT: Thanks for waiting, there is no reservation found under your name.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome, have a great day.