Organizational change and transformation is an important research topic that attracts the attention of many researchers and practitioners in organization research. This paper describes several case studies of applying DEMO in enterprise transformation. The enterprise transformation of divisions in Company A is analyzed to examine the relationship between Product-Market Growth Grid and business process change from the ontological perspective. The results indicate that (1) it is not always necessary to change the ontological level of business process in market development, (2) it is necessary to change the ontological level of business process in product development, and (3) it is necessary to reengineer the ontological level of business process in diversification. The generalizability of these results can be ascertained with more studies in future.