You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I be of your service?

USER: I want to change my existing reservation as I have a change of plan in my trip. Can you help me?

ASSISTANT: Sure, I can do that for you. May I know your name to proceed?

USER: I am James Carter.

ASSISTANT: Ok, please wait.

USER: Ok.

ASSISTANT: Thank you for being patient. There is no reservation found on your name.

USER: That's fine. No problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your service.