You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Michael Brown.

ASSISTANT: How may I help you for today?

USER: Previously I reserved a plane ticket with high fare but I want to cancel that ticket as there is special airline with low fare in my route.

ASSISTANT: Ok. Give me a second, I will check for your previous reservation.

USER: Ok.

ASSISTANT: Sorry to inform you that there is no reservation found on your name in our database.

USER: It's ok. Thank you for the information.

ASSISTANT: Welcome.