To my understanding, both configuration and change management systems are component of the organisation project management information system. However, the configuration management system consists of documented procedures employ in identifying, documenting and controlling changes to functional and physical characteristics of a product, service and results, including tracking system and approval level. On the other hand, a change management system defines how project deliverables and documentation is controlled, changed and approved. The latter is usually a subset of the former. See PMBOK Guide page 428-429.