The Contractor shall perform custodial services in accordance with the PWS and the technical exhibits (T.E.s). During performance of the contract the Government reserves the right to add or delete fac... The Contractor shall perform custodial services in accordance with the PWS and the technical exhibits (T.E.s). During performance of the contract the Government reserves the right to add or delete facilities and/or the level of services required. A modification to the contract will be executed to incorporate these changes.