I accidently did the quest for becoming a mooncloth specialist even though I'm a mage and want to have spellweaver specialization. According to a GM I spoke with it is possible to change the specialization but he cannot say where or how. Does anyone have a clue about this?
I think you have to go to the trainer you got the specialization from, unlearn, and then find the new specialist trainer. ISTR that it was in something from Blizz - probably one of the posts in the latest weekly.