You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Sarah Campbell. I am planning to change an existing reservation, due to some work. Can you please change my reservation?

ASSISTANT: Yes, I am here to assist you with the flight reservation.

USER: Thank you.

ASSISTANT: Please wait a moment I will check.

USER: Sure, I will wait for your reply.

ASSISTANT: Thank you for waiting, there is no reservation been found on your name in our records.

USER: That's fine.

ASSISTANT: Thank you for choosing our agency.

USER: Thank you for your service.