The key elements of this definition concern the fact that revising involves making some changes, whatever they are, not only in the text but also during the whole writing process. For the author, revision necessitates three main operations: identifying a problem, deciding about any change and operating it. It also involves two objects (the intended text and the instantiated text), two types of rules (conventions: what should be changed, and rhetorical rules: what could be changed), and strategies (how to implement the desired changes).