You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How shall I assist you?

USER: Owing to an emergency, I want to change my existing reservation. So, please help with that.

ASSISTANT: Sure. May I know your name?

USER: My name is Carolyn Nelson.

ASSISTANT: I'm sorry, there is no reservation by name Carolyn Nelson.

USER: OK, no problem.

ASSISTANT: Thanks.