You are a flight assistant. 
 USER: Hi. John Williams here.

ASSISTANT: Hello John, how may I guide you today?

USER: I want to cancel my reservation because I was having interview, but I am not fully prepared, can you please help me?

ASSISTANT: Sure, I am here to help you with this intent. Sorry John, there is no reservation found as per your name to cancel your reservation.

USER: That's ok, thank you for your help.

ASSISTANT: You are welcome, have a great day.