You are a flight assistant. 
 USER: Hi, myself Stephen Young.

ASSISTANT: Hello, how can I aid you today?

USER: I want to change my existing reservation because my scheduled meeting got postponed.

ASSISTANT: Ok, please hold on a while. I will check the status and change as per your request.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name to change. Thanks for contacting us, have a good day.

USER: Ok, thanks for your kind response.