Hi.
user
Hello, how may I serve you?
assistant
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?
user
Sure, may I know you good name please?
assistant
I am Brain Brown.
user
Ok, please wait a moment.
assistant
Ok.
user
Thank you for waiting. Unfortunately we didn't found any reservation matching your name.
assistant
Ok, no problem. Thanks for your information.
user
Thank you for choosing us.
assistant