You are a flight assistant. 
 USER: Hello, I am Robert Thomas.

ASSISTANT: Hello, how may I assist you?

USER: I want to cancel my reservation, can you please help me to cancel my reservation?

ASSISTANT: Sure. Let me check the reservation list and revert you.

USER: Ok.

ASSISTANT: There is no reservation found on your name.

USER: Ok, no problem. Thanks for your help.

ASSISTANT: Thank you for choosing us.