Hello @preciouswho
We appreciate your contact!
Roku devices can be controlled via an app on a phone or tablet. But such a device would have to be connected to the same network as the Roku.
However, if there are any changes on the network (SSID and password), you will need a physical remote in order to input your new password and connect to a new wireless network. For US customers, you can check out replacement remotes in our accessories store here
Hope this helps! Let us know if you have any other concerns.
Regards,
Karla