If you play normally, traits are permanent. You can however use the debug tool to toggle them. In "Key items" use the "Travel Sphere". Near the north-west corner there should be a set of orbs, and one of them is for toggling traits (exit from the central magic circle when you are finished).
Note that because traits are supposed to be permanent, some paths might still reference the traits even if you removed them (but you won't get new paths exclusive to the traits nor it will affect gameplay).