If their Webex boards keep losing connectivity, then I'd suggest that there are probably other issues afoot with the network or connection of the boards to the cloud, and that probably needs to be investigated rather than just adding in a reboot.
But, to answer the question, no, there isn't a native way on the devices to get them to perform a regular reboot. If you are on the latest code, you could probably use the Macro functionality to program a reboot, or you could use some other external device (ie a server or a PC to run a scheduled script to connect to each of them and issue a reboot).
Wayne
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