If you are trying to move devices from a different hub to Hubitat Elevation, you do not need the other controller to be online. You can exclude Z-Wave devices directly from the Hubitat hub:
For Zigbee devices, you can reset them individually, by following manufacturer's instructions.
If you no longer have the instructions for your specific device, be sure to check the following document:
https://docs.hubitat.com/index.php?title=Join_and_Reset_Instructions