@norman-vezey A Flic can be paired to multiple hubs/phones, but can only be connected to one hub/phone at a time. So, in order to pair to a different hub, you need to first temporarily disconnect from the first hub. In the Android app you can for each Flic button toggle Disconnect/Connect. But maybe it's easier to just unplug the first hub while you pair the button to the next hub.
When the Flic attempts to connect, it will pick the "first" hub that it detects.