Article 1361 addresses situations where a mutual mistake of fact causes the instrument to fail in disclosing the real agreement, making reformation a proper remedy.

Article 1360 states that principles of general law on reformation supplement the Civil Code's provisions. In cases of conflict, the Civil Code's provisions prevail.

Article 1359 defines reformation as a remedy when there's a meeting of minds, but the written instrument doesn't reflect the true intention due to mistake, fraud, inequitable conduct, or accident. If these issues prevent a meeting of minds, the proper remedy is annulment, not reformation. Reformation aims to correct the written instrument to match the parties' real intention.

The conditions for reformation include: a meeting of minds between the parties, the instrument not expressing their true intention, the failure of intention being due to mistake, fraud, inequitable conduct, or accident, and clear and convincing proof of these facts. The prescriptive period for filing an action for reformation is 10 years, as per Article 1144 of the Civil Code. Importantly, it's the written instrument that is reformed, not the contract itself.

Article 1362 covers cases where one party is mistaken, and the other acts fraudulently or inequitably, preventing the instrument from reflecting the true intention. Only the mistaken party can ask for reformation in this scenario.

Article 1363 is similar to Article 1362, but here, one party is mistaken, and the other, knowing the instrument doesn't state the real agreement, conceals that fact. The party in good faith (the mistaken party) can seek reformation.

Article 1364 allows for reformation when the failure to convey true intent is due to the ignorance, lack of skill, negligence, or bad faith of the person drafting the instrument (e.g., a drafter, clerk, or typist).

Article 1365 specifically addresses instances where parties agree on a mortgage or pledge, but the instrument mistakenly states it as an absolute sale or a sale with a right of repurchase. In such cases, reformation is proper to reflect the true agreement.

Reformation is not allowed in three specific cases: simple donations inter vivos with no conditions, wills, and when the real agreement made by the parties is void. These exceptions exist because donations are acts of pure liberality, wills are revocable and personal, and reforming a void agreement would be useless.

Article 1367 states that if a party has already brought an action to enforce an instrument, they cannot later ask for its reformation. This is based on the principle of estoppel, as enforcing the instrument implies acceptance of its terms.

Under Article 1368, reformation can be ordered at the instance of either party or their successor in interest if the mistake was mutual. Otherwise, if the mistake was not mutual, only the injured or innocent party, or their heirs and assigns, can petition for reformation.

Article 1369 concludes that the procedure for the reformation of instruments is governed by the Rules of Court promulgated by the Supreme Court.