Yes if you have a relationship with the sim still it means she is still in the game. Invite her over, add her to the household through marriage, socal interactions, or cheats. Resurrect her with a spellcaster, wishing well, book of life, cheats or ambrosia. Then kill her again with or without cheats. You have a new urn to play with. You can stop early if the sim trumps the urn. Easy.