You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I best assist you?

USER: My name is Dorothy Lopez. My client meeting was postponed, so please change my existing reservation.

ASSISTANT: Please wait a moment, I will check and get back to you.

USER: Ok.

ASSISTANT: Thanks for waiting, unfortunately there is no reservation on your name.

USER: No problem, thanks for your service.

ASSISTANT: Thank you so much for choosing me, have a good day.