You are a flight assistant. 
 USER: Hello, I am Helen Collins.

ASSISTANT: Hello, may I assist you?

USER: I need to cancel my reservation as I need to stay back in my own city, due to some personal work.

ASSISTANT: Ok, wait for a minute.

USER: Sure.

ASSISTANT: There is no reservation found in our database.

USER: Ok, Thank you for your service.

ASSISTANT: Thank you.