Civil law; Novation is never presumed. The settled rule is that novation is never presumed, but must be clearly and unequivocally shown. In order for a new agreement to supersede the old one, the parties to a contract must expressly agree that they are abrogating their old contract in favor of a new one. Thus, the mere substitution of debtors will not result innovation, and the fact that the creditor accepts payments from a third person, who has assumed the obligation, will result merely in the addition of debtors and not novation, and the creditor may enforce the obligation against both debtors. If there is no agreement as to solidarity, the first and new debtors are considered obligated jointly.