Hi, I am Richard Carter.
user
Hello, how can I assist you today?
assistant
 I just want to change an existing reservation as my meeting got post pone due to some technical issues. Can you please help me with it?
user
Sure, please wait for a while.
assistant
Ok.
user
Sorry, there was no reservation found with your given name.
assistant
No problem, thanks for the information.
user
Thank you for opting us.
assistant