Part 13: General Schedule 8: Permitted contract modifications Unforeseeable circumstances
Paragraph 4 provides that a modification is permitted if the circumstances giving rise to the modification could not reasonably have been foreseen by the contracting authority before the award of the contract. The modification must also not change the overall nature of the contract. The modification must not increase the estimated value of the contract by more than 50 percent. However, paragraph 4(2) provides that this 50 percent threshold does not apply if the contract is a utilities contract.