Hi, I am Michael Mitchell.
user
Hello, how can I help you?
assistant
 I need to change my recent existing reservation because of my conference has been postponed.
user
Ok, please wait for a moment.
assistant
Sure.
user
Thanks for waiting, sorry to inform you there is no any reservation found on your name.
assistant
Thank you for your valuable information.
user
Thank you, have a nice day.
assistant