Intelligent agents often have the same or similar tasks and sometimes they cooperate to solve a given problem. These agents typically know how to observe their local environment and how to react on certain observations, for instance, and this knowledge may be represented in form of rules. However, many environments are dynamic in the sense that from time to time novel rules are required or old rules become obsolete. In this article we propose and investigate new techniques for knowledge acquisition by novelty detection and reaction as well as obsoleteness detection and reaction that an agent may use for self-adaptation to new situations. For that purpose we consider classifiers based on probabilistic rules. Premises of new rules are learned autonomously while conclusions are either obtained from human experts or from other agents which have learned appropriate rules in the past. By means of knowledge exchange, agents will efficiently be enabled to cope with situations they were not confronted with before. This kind of collaborative intelligence follows the human archetype: Humans are able to learn from each other by communicating learned rules. We demonstrate some properties of the knowledge acquisition techniques using artificial data as well as data from the field of intrusion detection.