You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,. How can I serve you today?

USER: I want to cancel my existing reservation. Can you help me with that?

ASSISTANT: Sure,. May I know your good name please?

USER: I am David Wilson.

ASSISTANT: OK, please wait for a while.

USER: OK.

ASSISTANT: Sorry, I have not found any reservation in your name.

USER: OK, thanks for your service.

ASSISTANT: Thank you, for opting us.