The automotive industry is undergoing a major transition in Electrical/Electronic (E/E) architecture, evolving from traditional distributed and domain-based designs to zonal configuration. The rapid growth of software-driven functionality, cross domain function integration, and demands for centralized management have exposed the limitations of distributed and domain-based designs in complexity, scalability, and cost. Zonal E/E architecture addresses these challenges by consolidating computing and I/O resources into high-performance controllers distributed across physical zones of the vehicle, greatly reducing wiring complexity, improving modularity, and enabling scalable, software-defined vehicles. However, this transition cannot be immediate because vehicle design and electrical system solutions have been built on decades of distributed and domain-based development. Moreover, the enabling technologies for realizing zonal E/E architecture, such as high-speed automotive Ethernet, zonal power distribution, high-performance centralized computation platform and zonal controllers, and standardized software architecture, etc., are still maturing and being industrialized. To ensure safety, reliability, and cost-effectiveness, OEMs must follow a carefully planned evolutionary path to progressively consolidate functions, realizing the zonal design step by step. This paper proposes a structured framework and methodology OEMs could adopt to manage this E/E architecture transformation. The authors outline and discuss in detail the major stages of this evolutionary path, including horizontal and vertical integration, domain fusion, formation of mixed E/E architecture, continuous migration of functions into zonal controllers and centralized computation platform, and ultimately the full realization of zonal E/E architecture.