Hello.
Hello, may I know your good name please?
I am John Williams.
Thank you, What can I do for you today?
I need to change my recent reservation due to postpone of my college event  on 11/05. Could you please help me in doing that?
Ok, no problem. We can help you in changing your reservation.
Ok.
Sorry, no reservation has been registered with us on your name.
No worries, thank you for your valuable information.
Thanks for making an enquiry with us, have a nice day.