 In such a case, there is "consensus ad idem"; what is rectified is not the contract itself as a juristic act ("negotium"), but rather the instrument ("instrumentum") in question, because it does not embody what the parties intended to be the content of their agreement.Where a person enters into a contract on the strength of a misrepresentation made to him, or as a result of duress or undue influence by the other party, the agreement is nevertheless valid because there is no dissensus.Since the consensus was improperly obtained, however, the contract is voidable at the instance of the innocent party.