You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I help you?

USER: I have booked a ticket for vacation to Washington DC but my health is not good and I can not travel. Can you please help me to cancel my reservation?

ASSISTANT: Sure, may I know your name?

USER: My name is William Thomas from Denver.

ASSISTANT: William Thomas, we could not found any reservation on your name.

USER: That's not a problem.

ASSISTANT: Thank you so much for opting us.

USER: Thanks for your kind information.