5-14. A relief in place is an operation in which, by direction of higher authority, all or part of a unit is replaced in an area by the incoming unit and the responsibilities of the replaced elements for the mission and the assigned zone of operations are transferred to the incoming unit (JP 3-07.3). (Note. The Army uses an AO instead of a zone of operations.) The incoming unit continues the operation as ordered. Commanders conduct a relief in place as part of a larger operation, primarily to maintain the combat effectiveness of committed units. The higher echelon headquarters directs when and where to conduct a relief, and it establishes the appropriate control measures. The commanders participating in the relief in place communicate when the relieving commander has sufficient combat power and understanding of the AO to assume responsibility of the area.