This is the solution:
1) You will need the URL for your admin controls.
a) Navigate to the status tab of your signs in SAM.
b) Click on the 'gear' icon.
c) On the settings screen, below the QR code, click the link "Open Admin control"
The URL it takes you to can be typed into any web browser, (recommend Chrome), and gives you access to full Administration Privileges for your sign. This is a private URL individual to your sign.
2) When you copy and paste, or type the URL in a web browser, scroll down to the bottom, and find controls on the menu
3) This will open another menu. Find the menu item Reboot Device. This will allow you to reboot your device remotely
This will reboot your device remotely.