When there is a change in government regulations that affects a project, the project manager should first understand the new regulations and evaluate their impact on the project. This involves studying the new regulations with the team and assessing how they affect various project variables such as scope, cost, schedule, and quality. Once the impact is understood, the project manager can then make necessary adjustments to the project plan. References: PMBOKGuide, 6th Edition, Section 4.3: Direct and Manage Project Work, and Section 11.6: Control Risks.