In sims 3 how do you get the opportunity to bring your ghosts back to life at the science lab

I believe you have to have a sim be far along in the science carreer path and an opportunity comes up to bring a dead sim to the lab. To do that you have to have a grave on your lot and pull it into your inventory, not family inventory, but your personal one. Then you go to the lab and when you click on the lab you can report back for your opportunity. I have done this a while ago and I am 98% sure that's how it happened.