You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am William Jones.

ASSISTANT: What can I do for you William Jones?

USER: Due to my sudden change in my plan I want to cancel my reservation.Can you help me out with this?

ASSISTANT: Sure, Please hold on I will check the status and revert you.

USER: Ok.

ASSISTANT: Sorry there is no reservation found with your name.

USER: Not a problem.

ASSISTANT: Thank you for availing with us.

USER: Thanks  for your quick response.