Section 102 of BSA : Section 102: Who may give evidence of agreement varying terms of document.

Explanation using Example

Example 1:

A and B enter into a written contract where B agrees to sell A a specific quantity of rice, with payment to be made upon delivery. At the same time, A and B have an oral agreement that A will be given a discount if the rice is delivered late. This oral agreement cannot be used as evidence between A and B to alter the written contract terms. However, if C, a third party who has a financial interest in the timely delivery of the rice (perhaps because he has a subsequent contract with A), wants to show that the oral agreement exists because it affects his interests, he may be allowed to present evidence of this oral agreement.

Example 2:

D and E sign a written lease agreement for a commercial property, stating that the rent is to be paid on the first of every month. Concurrently, they have an oral agreement that E will provide D with a grace period of five days for the rent payment. This oral agreement cannot be used to change the written lease terms between D and E. However, if F, a neighboring tenant who has a clause in his lease that depends on the timely payment of rent by D, wants to show that the oral agreement exists because it affects his lease terms, he may be allowed to present evidence of this oral agreement.