This ongoing work investigates usage-based document reengineering as a means to support authors in modifying their documents. Document usages (i.e. usage feedbacks) cover readers' explicit annotations and their reading traces. We first describe a conceptual framework with various levels of assistance for document reengineering: indications on reading, problem detection, reconception suggestions and automatic reconception propositions, taking our example in e-learning document management. We then present a technical framework for usage-based document reengineering and its associated models for documents, annotations and traces representation.