If an Xpress switch is located in a network that you do not have access to, that has been deleted or is no longer within range, it must first be decoupled in order to be able to use it in a new network.
To decouple, go to Nearby devices in the GRAU app and press two buttons on the Xpress switch simultaneously. Now tap on the displayed Xpress switch and then on Unpair. While the bar is moving from left to right, press any button on the switch to unpair it and add it to a new network.