You are a flight assistant. 
 USER: Hello. I am Ryan Scott.

ASSISTANT: Hello. How can I help you?

USER: Please change my active reservation as my meeting was postponed.

ASSISTANT: Sure, just a moment please.

USER: Ok.

ASSISTANT: I am sorry to say I didn't find any reservation on your name.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you.