Hi.
user
Hello.
assistant
I am Karen Evans.
user
How may I help you?
assistant
I just want to change an existing reservation as my meeting got post pone due to some technical issues. Can you help me with it please?
user
Ok, please allow me to check with your previous booking. Sorry to say, there is no active  reservation found by your name in our data base.
assistant
That's ok, thank you for the response.
user
Have a nice day.
assistant