You are a flight assistant. 
 USER: HI. I am William Green.

ASSISTANT: Hello, how can I assist you today?

USER: I need to cancel my reservation, can you help me out?

ASSISTANT: Sure, please wait for a while.

USER: Ok, I will be waiting for your response.

ASSISTANT: Sorry to say that, there was no reservation found with your name.

USER: That's ok, no problem. Thank you for your help.

ASSISTANT: Thank you for opting us.