Can't remove Grim's Right hand trait

I didn't realize getting to the top of the Grim Reaper Career would make my Sim immortal. Retraiting potion won't get rid of it and the cheat code (traits.remove_trait trait_GrimsRightHand and other variations) doesn't seem to work. I would like this sim to be reborn, but need to find a way to kill them first.