Mutual mistake as basis for reformation
ART. 1361. When a mutual mistake of the parties causes the failure of the instrument to disclose their real agreement, said instrument may be reformed.
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(1) The mistake must be of fact (Art. 1331.), for if it is one of law, the remedy is annulment (Art. 1334.);
(2) Such mistake must be proved by clear and convincing evidence;
(3) The mistake must be mutual, that is, common to both parties to the instrument; and
(4) The mistake must cause the failure of the instrument to express their true intention.[2][3]
Moreover, in Vda. de Gonzales vs. Santos,[4] the Supreme Court held that relief by way of reformation of a written agreement will not be granted unless the proof of mutual mistake is of the clearest and the most satisfactory character. The amount of evidence necessary to sustain a prayer for relief where it is sought to impugn a fact in a document is always more than a mere preponderance of evidence.
[1] Reyes and Puno. Obligations and Contracts.
[2] De Leon. (2014) Obligations and Contracts.
[3] Bank of P.I. vs. Fidelity & Surety Co., 51 Phil. 57 (1927); Alaras vs. Court of Appeals, 64 SCRA 671 (1975); Cunanan vs. Antepasado, 5 SCRA 1028 (1962); Dizon vs. Gaborro, 83 SCRA 688 (1978).
[4] Vda. de Gonzales Mondragon vs. Santos, 87 Phil. 471 (1950).