Transformation of the orientational structure in a plane-parallel cell of a cholesteric
liquid crystal, was studied depending on the magnitude of the voltage applied to the boundary
planes of the cell. The equilibrium configuration of the liquid crystal director field was
found minimizing the free energy both analitically and numerically. We took into account
the orientational elastic energy in the volume and at the cell boundaries, the energy of an
inhomogeneous electric field, and the flexoelectric effect. Systems with large flexoelectric
coefficient were studied in detail. It was found, that when small voltages are applied to the cell
boundaries, a continuous Fredericks transition occurs first, and then, when certain characteristic
voltage is achieved, a significant jump-like change in the orientational structure takes place, and
this structure gradually changes with the further voltage increase. It is shown that various
scenarios of transformation of the orientational structure can be implemented depending on the
actual values of the set of material parameters of the system studied. The discovered ability to
control the structure of a liquid crystal in a cell can find use in various technical devices.