By issuing the xAPI command: xcommand systemunit FactoryReset Confirm: Yes
By removing the config.db file. (applicable with TC 7.0.X or earlier versions)
By using the Touch panel: More - Settings - Administrator Settings - Reset
Turn off unit (e.g by holding the physical power button pressed until it shuts down). Then hold the button for 10 seconds until it starts blinking. Now press the button twice. The unit will factory reset and restart.