You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER:  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 the trip. Can you please help me out with changing of my reservation?

ASSISTANT: Sure, can I know your name please?

USER: Myself Sarah Lee.

ASSISTANT: Sorry Sarah Lee, there is no active reservation found with your name in our records.

USER: That's fine, thank you for checking.

ASSISTANT: Most welcome.