Hi.
user
Hello, how may I assist you?
assistant
I want to change my existing reservation. Can you help me for this one?
user
Sure, I am here to assist you. May I know your name please?
assistant
Sure, Ryan Miller here.
user
I am really sorry to tell  you, there is no active reservation found with your name to change the details.
assistant
 No issues, thank you for the information.
user
My pleasure to inform you, thank you for opting us.
assistant