You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Dennis Williams.

ASSISTANT: Yes, Williams.

USER: I want to cancel my reservation, can you help in that?

ASSISTANT: Sure, I very glad to help you.

USER: Thanks.

ASSISTANT: Please wait a moment, let me check the reservation on your name.

USER: Sure.

ASSISTANT: Sorry Williams, no reservation found on your name in your data base.

USER: That's fine,might be my brother has canceled my reservation.

ASSISTANT: Thank you for reaching us.

USER: Thanks for your help.