This document provides an overview of Kurt Lewin's 3-stage change model of unfreezing, movement, and refreezing. It discusses each stage in detail and provides examples. Unfreezing involves letting go of old patterns by increasing driving forces for change and decreasing restraining forces. Movement is the process of changing thoughts, feelings, and behaviors. Refreezing makes the changes permanent and the new situation stable. The document also summarizes advantages of the model in being easy to understand and putting people first, and criticisms that it may be too simple or rigid. A case study of how Nissan used this model in its turnaround under Carlos Ghosn is also presented.