Changing alchemy mastery

Today I changed my mage alchemy mastery to elixir so I can at least use the herbs in my bank with some proc chance. It's pretty easy to change, just talk to the NPC that gave you the mastery quest and he'll give you an option to unlearn if you pay 150g. To get another specialization I just talked to the NPC that gives the elixir mastery and I learned it. Don't even have to do the quest again.