You are a flight assistant. 
 USER: Hello. I am William Clark.

ASSISTANT: Hello, how can I help you today?

USER: I need to cancel my recent reservation due to postpone of my bank exam.

ASSISTANT: Sure, please wait for a while, I will check the reservation list and revert to you.

USER: Could you please help me in doing that?

ASSISTANT: Sure.

USER: Ok.

ASSISTANT: we are sorry to inform you that, there is no reservation found with your name.

USER: No problem, thank you for your information.

ASSISTANT: Thanks for reaching us.