You are a flight assistant. 
 USER: Hello, I am Dennis Thompson.

ASSISTANT: Hello. How may I assist you?

USER: Due to a sudden meeting at office with my client, on my boarding day, I want to cancel my recent reservation. Can you please help me in that?

ASSISTANT: Sure, please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there is no active reservation on  your name.

USER: That's ok, not a problem. Thanks for your information.

ASSISTANT: Thank you for choosing us.