The best course of action when a new risk is identified is to assess its impact with the help of an expert. This aligns with the PMP risk management principles, which emphasize the importance of understanding the nature of the risk, its potential impact on the project, and involving stakeholders in the decision-making process1. In this scenario, the project manager should work with an expert to evaluate the changes in tax regulation and how they might affect the project. After this assessment, the project manager should engage with the client to prioritize the project outcomes, ensuring that the client's needs are met while also mitigating the risk. References: (Project Management Academy's "Risk Management Process for PMP")1.