Reforger NPC Abuse

[Ashestowishes]

Hello everybody, I would like to know the method on how to abuse the reforge on cata 4.3.4. As I see people abusing it to increase their stats with nobody knowing of their exploit. A video or brief explanation/steps would be nice. Thank you in advance

[Aeh']

When nobody knows their exploit, how would someone can tell you how it works?