You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you now?

USER: I have made mistake while booking the flight. Can you help me in changing my existing reservation?

ASSISTANT: Sure, may I know your name please?

USER: My name is Elizabeth Davis.

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

USER: That's fine, thank you for the information.

ASSISTANT: Thank you for approaching us, have a nice day.