Many real-time applications are designed to work in different operating modes each characterized by different functionality and resource demands. With each mode change, resource demands of applications change, and static resource reservations may not be feasible anymore. Dynamic environments where applications may be added and removed online also need to adapt their resource reservations. In such scenarios, resource reconfigurations are needed for changing the resource reservations during runtime and achieve better resource allocations. There are a lot of results in the scientific literature of how to find the optimal amount of resources needed by an application in the different operating modes, or how an application can perform safe mode transitions. However, the problem of resource reconfigurations for systems with reservations has not been addressed. A resource scheduler should be reconfigured online in such a way that it still guarantees a certain amount of resources during the re...