Short answer. You can ask a court to reform it. Article 1361 of the Civil Code provides that where a mutual mistake causes the instrument to fail to disclose the parties' real agreement, the instrument may be reformed — corrected to say what you both actually agreed, rather than cancelled.
What the law says
When a mutual mistake of the parties causes the failure of the instrument to disclose their real agreement, said instrument may be reformed.
Civil Code, Article 1361 — Reformation for Mutual Mistake. Read the full provision →
Reformation fixes the document, not the deal
The rule is one sentence: When a mutual mistake of the parties causes the failure of the instrument to disclose their real agreement, said instrument may be reformed. Reformation assumes there was a genuine meeting of minds and that the writing simply failed to record it. The court's job is to make the paper match the bargain — not to release you from the contract, not to improve your terms, and not to supply an agreement the parties never reached. That is why it is often the right remedy where a price, an area, a lot number, a date or a whole clause came out wrong on paper although both of you knew what had been settled.
"Mutual" is the load-bearing word here
This article applies where both parties laboured under the same mistake about what the instrument said. If only you were mistaken and the other side saw the discrepancy and stayed silent, that is a different provision with different elements. If the other side simply disagrees with you about what was agreed, there may be no mistake at all but a dispute over the terms themselves — and a signed document is a formidable opponent in that argument. And if both of you intended exactly what the paper says, and you now regret it, reformation offers nothing. Be clear which of these you are actually in before you spend money on the fight.
The proof a court will look for
A written instrument is presumed to contain the parties' agreement, so the burden on the person seeking reformation is a heavy one — courts look for clear and convincing evidence, not a plausible narrative. Gather the record that existed before signing and the conduct that followed it: quotations, computations, term sheets, earlier drafts and their revisions, the message thread around execution, and above all evidence that both sides afterwards performed on the basis of the true terms rather than the written ones. Payments made at the real price, or a property occupied to the real boundary, are worth more than recollection.
Limits, and why speed matters
Reformation presupposes a valid contract. Where the agreement is void, or where there was never a meeting of minds at all, the remedy is not to correct the writing but to have the contract annulled or declared ineffective. The Civil Code also places certain instruments outside reformation, including simple unconditional donations and wills. A party who keeps performing the written terms after discovering the error may find it harder to complain, and the action does not stay open indefinitely. So put the discrepancy in writing to the other side promptly, propose a corrected document, and take advice if they refuse.
Cases citing this provision
These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.
- Globe Asiatique Relaty Holdings Corporation vs. Union Bank of the Philippines, G.R. No. 229339, July 29, 2019 — read the decision on LawPhil →