how does reforging work in WoW cataclysm?

Answer 1

Reforging will allow you to reduce one of the current stats on an item by 50% and place those points into another stat.

Answer 2

World of Warcraft Cataclysm will introduce a new ability to professions that let them improve the stats on gear. Because simply adding new stats to gear would have made certain professions in too high a demand, Blizzard has decided to let crafters for most professions simply taken 50% of a certain stat on an item, and then put another stat on there for that same amount. This should allow for much more item customization possibilities in WoW Cataclysm. Here is some more info:
This new Reforging mechanic is added to most production professions.
Blacksmithing – Will change Plate armor and weapons
Engineering – Will change Ranged weapons and trinkets
Jewelcrafting – Will change Jewelry (rings, necklaces)
Leatherworking – Will change Leather armor
Tailoring – Will change Cloth armor
Reforging will allow you to reduce one of the current stats on an item by 50% and place those points into another stat.
The new stat cannot already be on the item; you can’t reduce stamina to add additional strength, but you can reduce stamina to add hit rating to the item, for example.

Reforging in WoW Cataclysm will allow the masters of these professions much more work on a daily basis, and should bring in some money to these expensive to develop professions. Players get yet another avenue to customize their characters. Sounds like a win-win to me.