You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: My name is Margaret Walker. I would like to change my reservation, could you help me out?

ASSISTANT: Please wait a while.

USER: Sure, take your time.

ASSISTANT: Sorry to say, there is no reservation on your name in our database.

USER: That's ok.

ASSISTANT: Thank you for opting us.

USER: Thank you for your help.