The Concept Space Maintainer is responsible for making modifications to the initial Concept Space. The changes that the Maintainer handles include additions, modifications and deletions of the items in the Concept Space. Corresponding results of these changes are learning, belief revision and unlearning respectively.
Once the Concept Space Maintainer executes an intention, it then creates a desire to inform the user about the action that it is taking. The Utterance Generator would then act on the corresponding intention to actually provide a feedback to the user. The importance of providing such feedback to the user is discussed in [BH95].