Is there a monetary threshold (limit) when a new requirement relating to a current contract cannot be modified into the contract, and when a new contract should be issued for the requirement? Is there a relevant FAR clause? For example the government procures phone services, which also requires the phone devices. The RFP mentions the device but offers no place to quote on the devices that are necessary, a contract is awarded for one base and four option years. A few months after the award the government uses that statement in the original solicitation (RFP) devices will be purchased separately, but adds the phone device purchase to the already contracted. The cost of the devices exceeds the award amount of the contract.