So I have a player who started out as a Shaman, but did some bad things that caused an aligment violation (poisoning the town werll in The Keep!). I took away all his magical powers. He atoned, but now he wants to change classes to Witch (the one that can control Undead; I think it's called Vouduon.or something like that). He's currently fourth level. Any suggestions on how to make this a smooth transition?
Shamans and witches are both divine casters and both can have links to ancestral spirits or animal spirits. Have the PC try to contact his/her ancestors (as per the shaman ritual and have it result in the defining of a new relationship with a particular ancestor. That ancestor becomes her new spirit guide and teacher and the PC becomes a witch.
If you want to formalize it in the game, have the PC train to get a new proficiency (soothsaying, say).