Hi. I am Nicholas Hernandez.
Hello, how may I help you today?
 I want change my reservation due to postpone of my  meeting.
Sure, we are here to help you. Please wait for a while, let me check your reservation and let you know.
 Ok.
Thanks for your time, unfortunately no reservation found with provided name.
Thank you for your response.
Thank you for availing us, have a pleasant day.