Confirmed quantity or reservation - What is correct concept

Dear Gurus,

I am facing the trouble between the concepts of confirmed quantity and reservation quantity. As I know material's quantities in SO will be confirmed after run ATP and TOR if stock quantity is enough, and see in stock requirement list this quantity is in confirmed. But I am not sure that confirmed quantity is different with reservation quantity for SO or not. If not how can I reserve this quantity for SO not by MB1C. I afraid that, other staff will create SO and delivery it before my SO can be delivered. Please explain for me in this case.

Thank for your support!