Reformation of instrument v. annulment

Reformation is that remedy by means of which a written instrument is amended or rectified so as to express or conform to the real agreement or intention of the parties when by reason of mistake, fraud, inequitable conduct, or accident, the instrument fails to express such agreement or intention.[1] In Veluz v. Veluz,[2] the Supreme Court laid down the differences between reformation of instruments and annulment of contract, to wit:
The reformation of instruments presupposes a valid, existing contract, in which there had been a meeting of the minds of the parties but the instrument drawn up and signed by them does not correctly express the terms of their agreement while annulment presupposes a defective contract in which the minds of the parties did not meet, or the consent of one was vitiated. Moreover, for the reformation of instruments, equity of reformation is ordinarily limited to written agreements, and its purpose is to establish and perpetuate the true agreement while annulment is intended to declare the inefficiency which the contract already carries in itself and to render the contract inefficacious.

[1] Reyes and Puno. Obligations and Contracts.

[2] Veluz v. Veluz, G.R. No. L-23261 (1968).