Influence Loss

[Obi-Wan Bologna]

So all this time I've been playing this game, (Years and years now) I've never seen where you can train someone or unlock other stuff from losing influence, but I've heard that if you lose enough influence with someone it's the same as gaining a bunch of influence with them. If so that would make training heavily bent (to the light or dark) characters much easier. Is this possible, and can someone go into more detail?