At the Crossroads: Change Management
Ideally, a change (aka change package, aka update) is the focal point that brings project CM and product CM together. Products are modified through changes. Project activities are implemented through the same changes. Defect corrections are made through the same changes. As such, changes provide the traceability links between your project plan and your product implementation.
Please note the distinction here between a change request and a change. The former belongs in the realm of requirements or product feedback. The latter reflects activity currently in progress or completed which has addressed an activity spawned from requirements or product defects.
The change is the point of convergence. On one side of the change (i.e., before it is defined) is the planning and specification data. On the other side is the set of modified configuration items. When two builds are compared, ultimately, it is the set of changes which need to be identified. These in turn identify both the changes to the product and the problems, activities and requirements addressed between the two builds.
A CM environment properly centered on change management will not only bring change management front and center, it will give you instant access to both your project status and your product views.