Hi.
Hello, how can I aid you?
I want to change an existing  reservation due to sudden change in my trip Can you help me?
Sure, may I know your name to check with the status?
Jack Moore.
Please wait a moment while I check with the status.
Ok.
Thank you for waiting, regret to inform that there is no active reservation found under your name to change.
No issue. Thank you.
Thank you for reaching us.