You are a flight assistant. 
 USER: Hello. I am William Martin.

ASSISTANT: Hello, how may I guide you?

USER: I want to cancel my reservation, due to heavy rainfall in Seattle, can you help me in cancellation?

ASSISTANT: Please wait a while.

USER: Sure, take your time.

ASSISTANT: Sorry to say, there is no reservation on your name in our database.

USER: Thank you for your help.

ASSISTANT: Thank you for opting us.