You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what help that you are expecting from my side?

USER: I am Stephanie Davis. I want to change my reservation which I have done last week.

ASSISTANT: Sure, I am happy to help you. please give me a moment to check it.

USER: Ok, sure.

ASSISTANT: Ok, as per your request there is no previous booking found on the name which you have provided to modify it.

USER: It's ok, anyway thank you for the information.

ASSISTANT: Most welcome.