The best first step is to assess the control state to determine why it is ineffective and whether adjustments, replacements, or compensating controls are needed. "Regularly assess the effectiveness of security controls to ensure they are providing the intended level of protection." - CISM Review Manual 15th Edition, Chapter 3: Information Security Program Development and Management, Section: Control Monitoring and Assessment* ISACA practice questions stress that assessing the control state comes before taking further action.