You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you today?

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, I am here to help you with this. May I know your good name please?

USER: Sarah Brown here.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry Sarah, there is no reservation found as per your name to change it in your database.

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

ASSISTANT: You are welcome.