You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I serve you at this moment?

USER: I want to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: Sure, I am here to help you. May I know your good name please?

USER: My name is Gregory Moore.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.