You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I am Richard Adams want to change my reservation  due to prepone of my business meeting.

ASSISTANT: Sure, please wait a moment, let me check your reservation and let you know.

USER:  Ok.

ASSISTANT: Thanks for your time, sorry, unfortunately no reservation found with provided name.

USER: Thank you for your information.

ASSISTANT: Thanks for opting us, have a great day ahead.