The statement "Ensures that all proposed changes are defined, reviewed, and agreed upon" relates to the process of Change Requests in project management. In this context, a Change Request is a formal proposal to modify an aspect of a project that has already been approved and is underway.

The statement emphasizes the importance of a systematic and thorough approach to managing Change Requests. This means that any proposed changes must first be defined, clearly articulating what is being changed, why it is being changed, and what the expected outcome of the change is. This ensures that everyone involved in the project has a clear understanding of what is being proposed and why.

After the proposed change has been defined, it must be reviewed. This involves assessing the potential impact of the change on the project and identifying any potential risks or issues that could arise. It is important to involve all relevant stakeholders in this review process to ensure that all perspectives are taken into account.

Finally, the proposed change must be agreed upon. This means that all stakeholders must come to a consensus about whether or not the change should be implemented. If the change is approved, it will be incorporated into the project plan and executed accordingly.

By ensuring that all proposed changes are defined, reviewed, and agreed upon, the project team can maintain control over the project and ensure that any changes are made in a strategic and coordinated manner, with full consideration given to potential risks and impacts.