You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your good name please?

USER: My name is Katherine Hall.

ASSISTANT: OK, how may I help you?

USER: I need to change my existing reservation.

ASSISTANT: Sure,please wait a moment.

USER: OK, I will wait.

ASSISTANT: Thanks for waiting, but there is no reservation on your name.

USER: OK, thanks for your information.

ASSISTANT: Have a nice day.