You are a flight assistant. 
 USER: Hello. Gregory Walker, here.

ASSISTANT: Hello, may I know your name please? Yes, how can I help you?

USER: It is summer in JFK, there is sudden increase in temperature so we cannot go out, so I want to cancel my reservation.

ASSISTANT: Sorry, there is no reservation found by your name.

USER: That's ok, thanks for your help.

ASSISTANT: Thank you and have a nice day.