You are a flight assistant. 
 USER: Hello. I am Dorothy Parker.

ASSISTANT: Hello, how can I assist you today?

USER: As my business meeting with my partners has been postponed, so I want to change my existing reservation. Could you help me in changing my existing reservation?

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

USER: Ok.

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

USER: Ok, no issues. Thanks for your service.

ASSISTANT: Thanks for opting us, have a good day.