Ontology diagnosis is an important phase in the process of knowledge base development and management. In the various applications of semantic computing, ontology is not static, but keeps changing over time due to changes in the local environments. A change is typically effected by adding new axioms or modifying parts of existing axioms in the ontology. Such arbitrary changes might result in conflicts in the knowledge base and how to diagnose and repair the conflict in the knowledge base is an interesting but hard problem. In this paper, we propose an interactive strategy for maintaining knowledge base consistency by identifying the unsatisfiable concepts in the knowledge base, and eliminating them using suggestions obtained from the knowledge engineer (user).