Can you revive someone who has already been reincarnated?

[Doctor.]

How would that work? Let's assume someone wants to revive Boo. Would the soul jump out of Oob's body and kill him? Would a soul just be created out of nothingness for Boo to use? Would the dragon refuse and say it's out of his power? What about Super Shenron?

[Black Hawk]

On Earth or on Namek, I expect Shen Long and Polunga would state that such a wish is beyond their power. Via Ultimate Shen Long or Super Shen Long, though, I think Boo and Oob would then coexist simultaneously; I'm not sure how to explain the in-universe mechanism for how this would work, but I expect this method is what the writers would choose.

[PerhapsTheOtherOne]

For the ordinary Dragon Balls, I would presume that this couldn't be done, simply because the Dragons would likely view the situation as "[X] person is no longer present in the Afterlife, so they cannot be revived because they're alive as a completely different person".

The Super Dragon Balls is an interesting case, though. They're not limited like the Earth and Namek Dragon Balls.

If it is indeed possible, it could be that a new soul is created that's identical to the one that was reincarnated albeit possessing the body of the person being "revived". Or it could be that the Dragon would simply refuse, citing the same reason I highlighted above.

[KBABZ]

Via Ultimate Shen Long or Super Shen Long, though, I think Boo and Oob would then coexist simultaneously; I'm not sure how to explain the in-universe mechanism for how this would work, but I expect this method is what the writers would choose.

I think the Ultimate/Super dragons would operate less on a "okay I need to work my magic and overcome this, this and this" and more like a MAGIC magic where it's like "yep, done, seeya". They're so powerful that it just works.

Now the interesting question would be if Super Shen Long would be able to delete the Omni King from existance. Is THAT above his power?

[Lionel]

I could see this coming down to an issue of specificity. Revival doesn't necessarily have to entail the soul being returned to a previous state of physicality in the living world. Shenron resurrected Freeza with his body mangled despite the clear intention being to revive him fully constituted. Something tells me all that would come back is the empty shell of Buu without the soul. It would more or less be just a useless husk of amorphous flesh and whatever else Buu is made up of.

[Whatever]

In Uub's case,nope unless its a time travel/wrap related wish like 'make it so Kid Buu was never reincarnated and ressurect him',most likely only possible through Super Shenron.Since Uub is a clean 100% reincarnation.

In Piccolo's case through,its more complicated and not as simple,since Piccolo Junior is both King Piccolo's son and reincarnation so he is not 100% King Piccolo in soul/essence(while Uub is 100% Kid Buu's reincarnation).In this case keep in mind that even if it was for a few seconds,PiccoloJr and King Piccolo coexisted.
So in this case its quite likely its possible to bring King Piccolo back to life with any set of dragonballs without it hindering Junior any way.

[Desassina]

What if the body was simply resting in a corner of the Otherworld waiting for it to be filled with another soul? Enma Daioh was able to bring back Vegeta, after all, when his body crumbled into pieces.