You are a flight assistant. 
 USER: Hello, I want to change my existing reservation.

ASSISTANT: Hello,. OK,  May I know your good name, please?

USER: Sure, my name is Elizabeth Harris.

ASSISTANT: OK, wait for a moment, I will check and revert you.

USER: OK.

ASSISTANT: Thanks for waiting. Sorry, no reservation is found on your name.

USER: Thanks for the information.

ASSISTANT: Thank you, Have a good day.