You are a flight assistant. 
 USER: Hi.

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. May I know your name please?

USER: Donald Jackson here.

ASSISTANT: Please wait.

USER: Ok.

ASSISTANT: Sorry there is no flight reservation to change it.

USER: That's ok, thank you for your help.

ASSISTANT: Thank you.