We present a mechanism to detect and resolve conflicts in virtual environments, populated by agents whose behaviours are regulated by norms, that is, explicit representations of obligations, permissions and prohibitions. A conflict arises when an action is simultaneously prohibited and obliged/permitted. We use first-order unification and constraint satisfaction to detect and resolve such conflicts, introducing a concept of norm curtailment. We present an algorithm for norm adoption which preserves conflict-freedom. Our approach allows us to address indirect conflicts and conflicts arising from the delegation of actions between agents.