Hello, I am Ruth Roberts.
user
Hello, how can I aid you?
assistant
I want to change my existing reservation due to postpone of my exam dates. Can you please help me with it?
user
OK, please wait I will revert you in a moment.
assistant
Sure.
user
 Sorry to inform you that no reservation was found on your name.
assistant
No problem, thanks for your information.
user
Thank you for availing us.
assistant