System Groups can be renamed by an administrator user even if they are used for security policies. The policies will not be affected.
Solution:
To rename a System Group follow these steps:
1. Log into Signals Notebook as an administrator
2. Navigate to 'Configuration' > 'System Groups'
3. Open the system group you wish to change
4. Click on 'Properties'
5. Double click on the value of the 'Name' property and start typing
6. The change will autosave once you click outside the text field