To help end-users master complex applications, it is often efficient to enable them to “replay” what they have done before. In some situations, it is even more useful to enable them to modify some values of the actions they are replaying so that they can see the consequences of the modification. Unfortunately, it is not always possible to replay series of actions after a modification of a prerequisite. Hence, the replay process has to deal with impact propagation of changes. In this paper, we describe our models to enable replay of user’s interactions and to manage impact propagation of changes during the replay process using impact rules to perform the adaptation. These models are built upon traces, i.e. digital objects that enable us to record user interactions and to reuse them in different ways. We have implemented the replay process in a Web application called SAP-BO Explorer, an application assisting business users in managing large amounts of information. Our tool helps users to better understand the application.