386. Discharge by alteration in terms or extent of the contract.

The surety will be discharged by any alteration in the terms of the building contract made after the contract of guarantee was signed unless such alteration was clearly not prejudicial to the surety1. A minor alteration made by the debtor for his advantage is not material2, and a surety will not be released because a recital in a specification states erroneously that it has been signed when it is immaterial whether or not the specification was so signed3.

A surety may also be affected by a variation requiring the contractor to carry out additional work or the grant of an