Hello, I am Nancy Smith.
user
Hello, how can I help you?
assistant
My exam has been postponed I want to change my existing reservation. Can you please help me with it/.
user
Sure, I am here to help you. Wait a minute, I will check and get back to you.
assistant
Ok.
user
Sorry to tell that there is no reservation on your name.
assistant
  Thank you.
user
Thank you for approaching us.
assistant