In recent years adaptive process management technolgy has emerged in order to increase the flexibility of business process implementations and to support process changes at different levels. Usually, respective systems log comprehensive information about changes, which can then be used for different purposes including process traceability, change reuse and process recovery. Therefore the adequate and efficient representation of change logs is a crucial task for adaptive process management systems. In this paper we show which information has to be (minimally) captured in process change logs and how it should be represented in a generic and efficient way. We discuss different design alternatives and show how to deal with noise in process change logs. Finally, we present an elegant and efficient implementation approach, which we applied in the ADEPT2 process management system. Altogether the presented concepts provide an important pillar for adaptive process management technology and emer...