The procedure by which one party in an action is replaced by another. This can be due to a number of reasons including death, incompetence, removal or resignation of someone being sued in his official capacity, etc.
civil law. In the law of devises, it is the putting of one person in the place of another, so that he may, in default of ability in the former, or after him, have the benefit of a devise or legacy.It is a species of subrogation made in two different ways; the first is direct substitution, and the latter a trust or fidei commissary substitution. The first or direct substitution, is merely the institution of a second legatee, in case the first should be either incapable or unwilling to accept the legacy; for example, if a testator should give to Peter his estate, but in case he cannot legally receive it, or he willfully refuses it, then I give it to Paul; this is a direct substitution. Fidei commissary substitution is that which takes place when the person substituted is not to receive the legacy until after the first legatee, and consequently must receive the thing bequeathed from the hands of the latter for example, I institute Peter my heir, and I request that at his death he shall deliver my succession to Paul. chancery practice. This takes place in a case where a creditor has a lien on two different parcels of land, and another creditor has a subsequent lien on one only of the parcels, and the prior creditor elects to have his whole demand out of the parcel of land on which the subsequent creditor takes his lien; the latter is entitled, by way of substitution, to have the prior lien assigned to him for his benefit. And in a case where a bond creditor exacts the whole of the debt from one of the sureties, that surety is entitled to be substituted in his place, and to a cession of his rights and securities, as if be were a purchaser, either against the principal or his co-sureties.
A surety on paying the debt is entitled to stand in the place of the creditor and to be subrogated to all his rights against the principal. In Pennsylvania it is provided by act of assembly, that in all cases where a constable shall be entrusted with the execution of any process for the collection of money, and by neglect of duty shall fail to collect the same, by means whereof the bail or security of such constable shall be compelled to pay the amount of any judgment shall vest in the person paying, as aforesaid, the equitable interest in such judgment, and the amount due upon any such judgment may be collected in the name of the plaintiff for the use of such person.