Rockwell Automation provides multiple options for migrating from an old automation system to their PlantPAx Process Automation System, including doing it all at once or in phases over time. They describe a multi-phase approach where they would first replace operator consoles with new HMI hardware and software while the existing controllers remain. The second phase adds new Logix controllers to operate alongside the existing system. The third phase completely replaces legacy controllers and I/O. Additional enhancements are also available to further improve performance and maintainability. Rockwell emphasizes working with customers to create a customized migration plan within their schedule and budget to maximize their competitive advantage.