Is there a way or cheat to make an old sim become adult again?

You can use the cheat "agesimscheat on", and then click on the sim, select "Set Age" and choose "Adult"

The SimBlender is great for that, otherwise type in "agesimscheat on" and click on the sim to select their desired age. Type in "agesimscheat off" afterwards.

Rulue, Aegagropilon, thanks for the answers, guys.

Keep in mind if you age him down to child or teen, he will be failing school--and still have whatever job he had before. It's best to have them quit work before re-aging in these cases, and then have them walk to school immediately before the social worker visit. Just in case, you weren't planning to age down to adult.

Although that is one way to seed the adoption pool...Just don't forget to get rid of the job and any marriages before aging them down that far!

Here's a thought - could I have an adult or elder, say from the family bin, on a college lot (either invited, or teleported with the teleporter cat - yeah, I just got it and I'm playing with it) and make them YA with this cheat?

I don't think the sim would be properly "enrolled" that way. Better to age him/her down to teen, then send him/her to Uni via one of the usual methods.

Regarding the aging down of sims in general, I've always been leery of the idea of aging them down younger than teen, due to the fact that kids and younger don't have LTWs yet. Seems like it might "confuse" the character file to get too drastic (like forgetting to have the older sim quit his/her job before being aged down!), potentially causing problems later. May just be me being paranoid, but I've learned that "better safe than sorry" is a good line to take with this game!

If you have SimPE or some other administrative software, though, can't you change the aspirations to "grow up" and erase the LTWs? And remove married status and so on?

I don't think most people bother, though. They just use the agesims cheat and call it good, and that's what I wouldn't do, personally.

I've never felt the need to age a sim back to younger than teen anyway, so I don't have any experience using SimPE to "fix" an aged-back sim. But I imagine it can be done.

I think it's funny that retired aged-down sims stay retired. I aged Olive Specter down to an adult and she still receives her pension. The game didn't even change it to maternity pay or do any of the usual "Now that a little one's on the way..." pop-ups while she was pregnant with Asphodel.

sims can retire before they reach elder. So the game has no issue with de-aged sims who are retired.

Not in an unmodded game. Retirement is a perk of elderhood.

To my knowledge, I don't have a mod that allows early retirement. Is it because I have mods that slow or stop aging?

One of Pescado's mods, I forget which, counts the days to elderhood and, if you have enough vacation days to cover it, it lets you retire as an adult. The retirement won't show on the work panel until the sim ages to elder, but the pension comes in just fine.

@Darby Ferfil retired while she was preggers I never aged her down

But a simpler way is to Shift click a sim, spawn, and there will be somehwere in there a option for Sim Modder if you clicked the right one it will look like a creepy baby. You can age your sims down (and up for that matter) with that. YES if you go to school age you WILL be failing but you can pick up your grades like any failing child. This does NOT effect college at all if you age to a teen wait a day or two then go to college. I have learned with the Goodie couple though if your married before aging down you will STAY married that will nto change.. If you retire before ageing down you will stay retired. So far, knock on wood, I havn't had any ill effects of this.

Oh special note, if you age down I advise you to quit your job or retire or your carpool WILL show up.

Wonder if you can retire and go to teen keep your retirment fund and go to college.... SIM TIME!

Okay I just learned failing sims cannot go to college and I am to tired right now to raise her grades.

What about this? Does anyone here use this mod?