The first course of action for a risk practitioner when discovering a deficiency in a critical system that cannot be patched is to conduct a risk assessment. A risk assessment is a process of identifying, analyzing, and evaluating the risks that could affect the achievement of the objectives of the system or the organization. A risk assessment helps to determine the level and nature of the risk exposure, and to prioritize and respond to the risks. Conducting a risk assessment is the first course of action, as it helps to understand the source, cause, and impact of the deficiency, and to estimate the likelihood and consequences of the risk events that could exploit the deficiency. Conducting a risk assessment also helps to identify and evaluate the existing or potential controls or mitigations that could address the deficiency, and to recommend the appropriate risk treatment options. Reporting the issue to internal audit, submitting a request to change management, and reviewing the business impact assessment are not the first courses of action, as they are either the outputs or the inputs of the risk assessment process, and they do not address the primary need of assessing the risk situation and status. References = CRISC Review Manual, 6th Edition, ISACA, 2015, page 49.