When an organization is assessing the use of agile delivery approaches and a decision is made to shift from Scrum to a predictive approach, it is essential for the project manager to define a project management plan that reflects this new approach. This involves updating or creating new plans to cover aspects such as scope, schedule, cost, quality, resources, communications, risk, procurement, and stakeholder engagement to align with the predictive methodology. The project management plan serves as a roadmap for the project and guides the team on how to execute, monitor, and control the project. It is critical to ensure that the plan is comprehensive and integrates all aspects of the project management processes and knowledge areas as outlined in the PMBOK Guide.
PMBOK Guide - Sixth Edition, Section 4.2 Develop Project Management Plan; Agile Practice Guide.