When an outcome is no longer in active use, there are three options which are available:
Marking the outcome as Obsolete
Hiding the outcome
Deleting the outcome
The first two options are often used in tandem, as they affect the outcome in different ways. Deleting an outcome, though possible, is not normally recommended, as it requires the deletion of all affiliated data (Measures, Findings, etc.)
For more information on these options, as well as instruction on how to process such changes, please see the video below. Click CC for captions and click the expand icon (lower right) for full screen.