Hi.
Hello, how may I serve you?
Actually I made a earlier reservation to go for a trip with my friends, but heavy work  in office I want to change my reservation. Can you help me in changing an existing reservation?
Sure, may I know you good name please?
I am Brain Brown.
Ok, please wait a moment.
Ok.
Thank you for waiting. Unfortunately we didn't found any reservation matching your name.
Ok, no problem. Thanks for your information.
Thank you for choosing us.