You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Christopher Williams.

ASSISTANT: How can I help you at this moment?

USER: I want to cancel my recent reservation. Could you help me with that?

ASSISTANT: Sure, I am here to help you with that. Please, give me a moment.

USER: OK.

ASSISTANT: Sorry, there are no flights available as per your specifications.

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

ASSISTANT: Thank you for opting us.