You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I want to change my existing reservation, can you be my helping hand to book a flight?

ASSISTANT: Sure, May I know your good name please?

USER: I am James Young.

ASSISTANT: Ok, Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, There is no reservation found by your name.

USER: Ok, Thanks for your information.

ASSISTANT: Thank you have a nice day.