The partial integration rule applies to instances in which part of the contract is written. [Baysden v. Roche, 264 Va. 23 (Va. 2002)].
Partial integration rule states that where the entire agreement has not been reduced to writing, parol evidence with respect to a part of a whole transaction not reduced to writing, is admissible although not admissible as to the part reduced to writing. However, such evidence should not contradict or vary the terms of the instrument. [Lewis v. Roper, 579 P.2d 434, 438 (Wyo. 1978)].