You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

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

ASSISTANT: Sure, can I know your name please?

USER: My name is Jeffrey Miller.

ASSISTANT: Sorry, there is no reservation found on your name.

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

ASSISTANT: Thank you for approaching us.

USER: Welcome.