Mage Job Change Guide
1. The mage job quest NPC is located in Geffen in the northwest building (geffen 63, 177).
2. Once inside, talk to the girl by the blackboard. She will tell you what solution number you need. The solution number you get determines what items you need and what you need to input in to the mixing machine. You can look up the ingredients you need at the book shelf located inside of the same room.
Note: The catalyst item isn't needed, it is just a selection from the mixing machine list.
Milk can be obtained in Prontera at the Milk Merchant (76, 133) for 25z.
The Payon Solution is found in the Payon Archer Village (the Archer Village is accessible through the top right portal of Payon). The NPC, named Dollshoi, is located at (118, 100).
The Morroc Solution is found in the Pyramids map located in the north west corner of Morroc. The NPC, named Ponka-Hontas can be found at (88, 147).
3. After obtaining all of the ingredients, mix them in the the mixing machine (??, ??) back at the Mage Guild. Make sure to double check the ingredients, catalyst, and mixing code. If a mistake is made at this time, all of the items will have to be gathered again.
4. Once the Unknown Solution is made talk to the main quest NPC again. If you give her the correct solution, she will change your job to Mage.