Hello.
Hello. How can I assist you at this moment?
I want to change my existing reservation due to bad weather condition, can you please help me with that?
Sure, I am happy to help you with that. Can I have your good name please to  check your reservation status?
My name is David Harris.
Ok, please wait a moment.
Sure.
Sorry David Harris, no reservation has found under your name to change.
No problem, thank you.
Thank you for choosing us, have a good day.