You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Donna Anderson. I have to do some modification in my previous flight ticket booking that there is a sudden event held at my home town, so I am unable to travel to the trip. Can you please help me out with changing of my reservation?

ASSISTANT: Sure, I am here to help you with this. Sorry Donna, there is no reservation found as per your name to modify it.

USER: That's fine, thanks for your valuable information.

ASSISTANT: You are welcome always.