The personnel and/or facilities listed below (or as specified in the Schedule of this contract) are considered essential to the work being performed hereunder. Prior to removing, replacing, or diverting any of the specified individuals or facilities, the Contractor shall notify the Contracting Officer reasonably in advance and shall submit justification (including proposed substitutions) in sufficient detail to permit evaluation of the impact on this contract. No diversion shall be made by the Contractor without the written consent of the Contracting Officer; provided, that the Contracting Officer may ratify in writing the change and such ratification shall constitute the consent of the Contracting Officer required by this clause. The personnel and/or facilities listed below (or as specified in the Schedule of this contract) may, with the consent of the contracting parties, be amended from time to time during the course of the contract to either add or delete personnel and/or facilities, as appropriate.