According to the best practices in project management, when facing significant changes that impact project timelines, the project manager should first assess the situation with the project stakeholders. This involves analyzing the new circumstances, evaluating the potential impact on the project delivery, and exploring alternative solutions or adjustments to the project plan. Once a clear assessment is made, the project manager should then communicate the impact to the customer, providing them with the most accurate and updated information. This approach ensures that the customer is informed of the situation based on a thorough analysis and collaborative effort, rather than a hasty, unilateral decision by the project manager.
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PMI's Code of Ethics and Professional Conduct emphasizes the importance of responsibility, including making decisions and taking actions based on the best interests of society, public safety, and the environment1.
The PMBOKGuide highlights the need for project managers to engage with stakeholders to understand their needs and expectations, and to manage their engagement throughout the project2.
The PMI Guide to Business Analysis states that business analysts should work with stakeholders to define requirements and shape project outputs3.
1: PMP Examination Content Outline - June 2019 - Project Management Institute 2: A Guide to the Project Management Body of Knowle