An Active Plan contains a copy of an Action Plan or a Maintenance Schedule and exists only during the duration of the execution of either base plan. The purpose of these objects is to decouple running activities from editing activities that can occur at the same time. Thus any changes made on the base objects has no effect on the current execution of any activities when they started.
There is no user interface for these objects, as they work in the back ground, and any traces and display of maintenance activities reference the base objects even they are originated from the active plan objects. The only hint that they exist can be seen in the “Working” tab in the “Detailed List” Window.