The document summarizes the three phases of the change management process according to Lewin and Schüppel. Lewin's three phases are: 1) Unfreezing, where the need for change is established and resistance is reduced; 2) Moving, where the change is implemented and new behaviors are formed; 3) Refreezing, where the new changes are stabilized and integrated into the organizational culture. Schüppel expands on the preparation phase with substeps like defining a vision and barriers. The planning phase includes designing measures and pilot processes. The execution phase involves monitoring and maintaining learning. An example from the author's company illustrates issues that can arise when these phases are not properly followed.