You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Owing to an emergency, I would like to change my existing reservation. Can you help me to change it?

ASSISTANT: Sure, I will help you. Please wait for a moment.

USER: Sure, my name is Carol Garcia.

ASSISTANT: May I know your name please?

USER: I have already provided.

ASSISTANT: Please wait for a moment.

USER: Sure.

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

USER: That's Ok, thanks for your information.

ASSISTANT: You are welcome, have a nice day.