Hi.
user
Hello. How may I help you?
assistant
 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?
user
 If you can help me with your name, I can check with the availability of flights.
assistant
Raymond Robinson here.
user
 I am very sorry to inform you that there is no reservation found under your name in our database.
assistant
That's ok, thank you for your help.
user
Thank you for choosing us.
assistant