: From a maintenance perspective, only software that is well understood can evolve in a controlled and high-quality manner. Software evolution itself is a knowledge-driven process that requires the use and integration of different knowledge resources. The authors present a formal representation of an existing process model to support the evolution of software systems by representing knowledge resources and the process model using a common representation based on ontologies and description logics. This formal representation supports the use of reasoning services across different knowledge resources, allowing for the inference of explicit and implicit relations among them. Furthermore, an interactive story metaphor is introduced to guide maintainers during their software evolution activities and to model the interactions between the users, knowledge resources and process model.