While holding the Talk and Volume buttons, press and hold the Power button
Relay will announce that Factory Data Reset will begin soon
After 10-15 seconds of holding the buttons, Relay will reboot and begin to reset
Factory Data Reset is used to reset the Relay to its factory state to clear unexpected software issues. Note, this will not allow it to move to another account. It must be (re)activated on the originally activated account to be available for use.