In this paper we address the operator assignment/reassignment problem in incremental cell formation. In incremental cell formation, cells are created based on parts and products that have high contributions. When these are created, it is necessary to assign operators, both from existing cells and new operators to work in the new cells. We consider three scenarios, where in the first we consider the assignment of operators to the new cells only. In the other two scenarios, we consider reallocation of operators to the existing cells if some operators from these are allotted to new cells. We show integer programming and network formulation for the three scenarios. We also test the network problems using randomly generated large sized problem instances.