Hi.
Hello. How may I aid you?
I am Donald  Williams. I want to change an existing   reservation due to sudden change in my trip. Can you help me?
Sure, I am perky to help you.
Thank you.
Please, wait for a while.
Ok.
Sorry, there is no reservation found on your name in our records.
No issue. Thank you.
Thank you for choosing us, have a great day.