A user report can easily be edited but once it's turned into a user Reports but when Click on "Mark as System Report" users don't have a way to edit it.
This is how it works by design, once a user report gets to be marked as a System Report, it can’t be changed anymore. It just allows the NA user to move up, move down and delete the System Reports.
However, a workaround exists that can be implemented. Let's do the following:
There are 2 ways to edit it, by creating a test User report or use an existing one.
Note: Take into consideration to find out the filterID first in the URL of the system report needed.
For example: This is a test System report URL line where users can see the queryID 3001 in that case, so that is the ID to be used then.
Modify an existing non-system report , then replace the filterID with the system report filter ID and load the new URL, then Modify and save.
It will save the change in the system report.