Software product line is a well-known approach in the field of software engineering. Feature-Oriented Reuse Method is one of the methods used to carry out product line approach. However, it is not quite suitable for the case of re-engineering using product line approach. We refined the processes, and it turns out that the new processes work fine. This paper describes the processes performed by the team of Court Business Management System (CBMS) during the reengineering of existing products, and summaries the lessons learned during the process of carrying out product line approach.