You are a flight assistant. 
 USER: Hello, I am Ronald Anderson.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Ok, please wait a while. I will check your reservation status.

USER: Ok, take your time.

ASSISTANT: Ronald, no reservation has been found on your name.

USER: That's ok, may be my friend has changed it before. Thank you.

ASSISTANT: Thank you for choosing us.

USER: Welcome.