No you can't, but you can release them, they are still alive. They can, in some small way, be compensated. Once you kill someone, that's it. Death is permanent.
In the end, we need to evaluate the pros and cons of the death penalty, and really there are very few pros. It's expensive, it's not a deterrent, it does not offer society on whole any more protection/safety than life in prison without parole, its failure mechanism is the state sponsored killing of innocent people. What are the pros? Some emotional satisfaction of killing a bad guy....that's pretty much it.
So in the end, all these negatives and it's completely ineffective, yet we know that at least 156 couldn't be shown to be guilty of their crimes. Who know how many other innocents died that we couldn't figure out. So there is no point to the system at all. It's cheaper, easier, and just as effective to keep an inmate locked in jail than it is to kill them.