According to A Guide To Schedule Updating in Project Management, one of the best practices for effective schedule updating is to perform an impact analysis before making any changes to the schedule. An impact analysis helps the project manager to assess the effects of the change on the project scope, cost, quality, risk, and stakeholder expectations. It also helps to identify the best options for resolving the issue and minimizing the negative impacts. By performing an impact analysis first, the project manager can make informed decisions and communicate them clearly to the project team and stakeholders.