If you would like to reset the macOS Client you need to do the following:
Click on Finder from the Dock
Select Go from the top left menu bar
Select Go to Library
Type in ~/Library
Extend 'Application Support'
Drag and Drop the Signagelive folder to the trash.
Please Note
If you would like to remove the Signagelive Client entirely, then you will need to clear the file system and uninstall the app.