Organizational change occurs when a company transitions from its current state to a desired future state. There are various reasons for organizational change, including changes in business conditions, management, existing structures, technology, government policies, and scope. Lewin's three-stage model of planned change includes unfreezing the current state, changing to a new state through learning new behaviors and attitudes, and refreezing the new state through reinforcement. Similarly, Kotter's eight-step change model outlines key activities like creating urgency, forming a coalition, communicating a vision, empowering change, creating short-term wins, and anchoring changes in corporate culture. Managing organizational change effectively requires understanding change processes and motivating employees through the transition.