We consider the Windows Scheduling problem. The problem is a restricted version of Unit-Fractions Bin Packing, and it is also called Inventory Replenishment in the context of Supply Chain. In brief, the problem is to schedule the use of communication channels that allow at most one transmission per time slot, to clients specified by a maximum delay between consecutive transmissions. We extend previous online models, where decisions are permanent, assuming that clients may be reallocated at some cost. We present three online reallocation algorithms for Windows Scheduling. We analyze one of them and we evaluate experimentally all three showing that, in practice, they achieve constant amortized reallocations with close to optimal channel usage. Our simulations also expose interesting trade-offs between reallocations and channel usage. To the best of our knowledge, this is the first study of Windows Scheduling with reallocation costs.