You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I would like to change my existing reservation, which is done recently. Can you please help me out?

ASSISTANT: Sure, I will help you with that.

USER: Thank you for considering my request.

ASSISTANT: May I know your name please?

USER:  Myself Andrew Lee.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

USER: That's ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your service.