Quite easily.
Let's presume that restoration and rehabilitation must take place before we die (just to remove reincarnation and other issues).
First, at least in the US, it takes about 10 years from sentencing to execution. That 10 years is quite a while. Obvioulsy enough time to seek restoration and rehabilitation, if that is what the murdeer wishes.
From a restoration and rehabilitation standpoint, the death penalty is like any early or earthly death, in that not matter the method of our deaths, be that by cancer, car wreck, execution, old age, etc., we only have the time of our lives within which to seek rehabilitation and restoration.
3) “. . . a secondary measure of the love of God may be said to appear. For capital punishment provides the murderer with incentive to repentance which the ordinary man does not have, that is a definite date on which he is to meet his God. It is as if God thus providentially granted him a special inducement to repentance out of consideration of the enormity of his crime . . . the law grants to the condemned an opportunity which he did not grant to his victim, the opportunity to prepare to meet his God. Even divine justice here may be said to be tempered with mercy.” Quaker, biblical scholar Dr. Gervas A. Carey (1) (p. 116).
4) Romano Amerio, a faithful Catholic Vatican insider, scholar, professor at the Academy of Lugano, consultant to the Preparatory Commission of Vatican II, and a peritus (expert theologian) at the Council.
“The most irreligious aspect of this argument against capital punishment is that it denies its expiatory value which, from a religious point of view, is of the highest importance because it can include a final consent to give up the greatest of all worldly goods."
"This fits exactly with St. Thomas’s opinion that as well as canceling out any debt that the criminal owes to civil society, capital punishment can cancel all punishment due in the life to come. His thought is . . . Summa, ‘Even death inflicted as a punishment for crimes takes away the whole punishment due for those crimes in the next life, or a least part of that punishment, according to the quantities of guilt, resignation and contrition; but a natural death does not.’ "
"The moral importance of wanting to make expiation also explains the indefatigable efforts of the Confraternity of St. John the Baptist Beheaded, the members of which used to accompany men to their deaths, all the while suggesting, begging and providing help to get them to repent and accept their deaths, so ensuring that they would die in the grace of God, as the saying went.” (2)
Some opposing capital punishment ". . . go on to assert that a life should not be ended because that would remove the possibility of making expiation, is to ignore the great truth that capital punishment is itself expiatory. In a humanistic religion expiation would of course be primarily the converting of a man to other men. On that view, time is needed to effect a reformation, and the time available should not be shortened. In God’s religion, on the other hand, expiation is primarily a recognition of the divine majesty and lordship, which can be and should be recognized at every moment, in accordance with the principle of the concentration of one’s moral life.” (2)
Some death penalty opponents “deny the expiatory value of death; death which has the highest expiatory value possible among natural things, precisely because life is the highest good among the relative goods of this world; and it is by consenting to sacrifice that life, that the fullest expiation can be made. And again, the expiation that the innocent Christ made for the sins of mankind was itself effected through his being condemned to death.” (2)