You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

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

ASSISTANT: Please share your name?

USER: My name is Paul Hill.

ASSISTANT: I am sorry to say, no reservation found on your name.

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

ASSISTANT: Thank you.

USER: Welcome.