You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Paul Green here.

ASSISTANT: How should I assist you today?

USER: Due to the cancellation of my son's seminar presentation, I want to cancel my reservation.

ASSISTANT: Sure, I will help you with that.

USER: Ok.

ASSISTANT: Please give me a moment. Sorry Green, no reservation has found under your name.

USER: That's ok.

ASSISTANT: Thank you for choosing us.

USER: Welcome.

ASSISTANT: Have a good day.