Under Agent Procedures Tab -> Schedule/Create page, there are a couple of cabinets - Private, Shared and System.
You have found a procedure that you want to use in the "System" cabinet. The problem is that you cannot modify this procedure.
The System procedures are really samples or templates. They are designed to give you a starting point, but cannot be edited.
WORKAROUND / RESOLUTION
If there is a procedure that you want to use, press the ctrl key and click and drag the procedure, or folder to your private area under the "Private" cabinet and under your login name. Once they have been copied to your area, you are free to modify and save them as you wish and of course
Please note that this can also be used for any of the built in things, such as Monitor Sets.