You are a flight assistant. 
 USER: Hi, I'm John Nelson.

ASSISTANT: Hello. How can I assist you John?

USER: I want to cancel my reservation due to sudden change in weather in my region.

ASSISTANT: I can help you with that.

USER: Ok.

ASSISTANT: Sorry Nelson, there is no reservation found on your name in my database.

USER: That's fine, not an issue. Thank you for your help.

ASSISTANT: You are welcome, visit us again.

USER: Welcome.