You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: As I have planned for a holiday vacation, but suddenly I did not get permission in my office.

ASSISTANT: Ok.

USER: Help me in changing my reservation.

ASSISTANT: Please mention your name.

USER: I am Joseph Campbell.

ASSISTANT: Ok. Please wait.

USER: OK.

ASSISTANT: Thanks for waiting, we could not found your name in the list.

USER: Its ok, thank you for your assistance.

ASSISTANT: Thank You.