You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Robert Moore.

ASSISTANT: How may I aid you?

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 out.

USER: Thank you.

ASSISTANT: Robert Moore, we haven't found any reservation under your name  in our database.

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

ASSISTANT: Thank you for reaching us.

USER: Welcome.