Hi.
Hello, how can I help you at present?
 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?
Sure, I can change your reservation right now. Before that I need to know your good name please?
David Moore here.
Sorry to say that, there is no active reservation found on your name.
That's ok, thank you for your help.
Thank you for choosing us.