How to Derank someone in Call of Duty Black Ops

Okay, this is SO mean. But if you've got a friend (perhaps a frenemy) who annoys the hell out of you then you can pull this super awesome XBox 360 Call of Duty Black Ops prank. Your friend needs to be level 50 (doing combat training) in order for this to work.

Now what does this prank do exactly? Well, if done successfully it will drop your level 50 friend back down to level 1 of their current pretige level. Sinister, we know.