You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am David Clark.

ASSISTANT: How can I assist you?

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

ASSISTANT: Sure, let me check your reservation status.

USER: Sure.

ASSISTANT: Sorry, I did not find any reservation under your name.

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

ASSISTANT: You are welcome.