2 ways to do that
1 - Unplug unit, as it's booting into portal hit the menu button (bottom left of arrows) and then access the settings menu by booting the embedded portal - think thats what it says on screen and once booted there go into the Settings menu, the portal and adjust there.
or
2 - When you come to the screen about free trial ending, hit the setup button, then select portal and change settings there. Save, then reload portal or device which ever you prefer and you should be on your way