Hi.
Hello, how may I help you?
I want to change my existing reservation which is done recently due to some problems, can you please help me in this?
Sure, I am here to help you with that, can I know your good name to proceed further?
Sure, my name is Janet Turner.
 I am very sorry to inform you that there is no reservation found under your name in our database.
Ok, no problem. Anyways, thank you for your service.
Thank you for reaching us.