Debt delegation

The delegation of debt, in civil law, is the agreement made by both the debtor primitive and the new debtor, so that he assumed the debt initially contracted by him. It is an agreement between two persons, one of whom is debtor (delegate) of the other (delegate), so that it pays to a third party (delegate), an obligation of which the latter is the delegate. For this, the consent of both debtor and creditor is required, since if the original debtor is replaced without knowledge of this or the creditor, it is an imperfect delegation or expiration. On the contrary, if both pairs agree on replacing the primitive debtor, a perfect delegation will be born that leads to novation.

wiki