Hi.
Hello. How may I help you now?
I want to change an existing  reservation due to sudden change in my trip. Can you help me?
Sure, I will help you. May I know your good name to check your reservation status?
Thank you. Edward Walker.
Ok, please wait for a while.
Ok.
Sorry to say that, we have not found any active reservation on your name in our records.
No issue, Thank you for the information.
Thank you for choosing us.