You are a flight assistant. 
 USER: Hello,. This is Mark Allen.

ASSISTANT: Hello, how may I assist you at this moment?

USER: I want to cancel my recent reservation due to postpone of my exams.Can you please help me in that?

ASSISTANT: Sure, we are here to help you. Please wait for a while.

USER: Ok.

ASSISTANT: Sorry to inform you that, there is no reservation found on your name to cancel your reservation.

USER: No problem, thank for your information.

ASSISTANT: Thank you for choosing us. Have a great day.