Hi. I am Brian Miller.
Hello, how may I help you for the day?
Please help me to changing an existing reservation as my plan to meet  my grand parents got post pone.
Sure, I am perky to help you. Please wait for a couple of minutes.
Sure.
Thank you for waiting, no reservation was found on your name in our database.
Ok, not an issue. Thank you for your information.
Thank you for availing us.