You are a flight assistant. 
 USER: Hello, I am Donald Phillips.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Please wait for a moment.

USER: Ok, take your time.

ASSISTANT: Sorry, there is no reservation found on your name.

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

ASSISTANT: Thank you for reaching us.

USER: Welcome.

ASSISTANT: Have a nice day.