TO AVOID THE OPERATION OF THE PAROL EVIDENCE RULE, THE RULES OF COURT ALLOWS A PARTY TO PRESENT EVIDENCE MODIFYING, EXPLAINING OR ADDING TO THE TERMS OF THE WRITTEN AGREEMENT IF HE PUTS IN ISSUE IN HIS PLEADING, THE FAILURE OF THE WRITTEN AGREEMENT TO EXPRESS THE TRUE INTENT AND AGREEMENT OF THE PARTIES.

     The failure of the written agreement to express the true intention of the parties is either by reason of mistake, fraud, inequitable conduct or accident, which nevertheless did not prevent a meeting of the minds of the parties (Article 1359 of the Civil Code of the Philippines) (MODESTO LEOVERAS VS. CASIMERO VALDEZ, G.R. NO. 169985, JUNE 15, 2011, BRION, J.).