How do I removed a MAC address from an approved list on my Ruckus Smartzone

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I have a guest wifi that is set to allow by MAC address to the ssid.  Now that it is working fine, I was asked to remove a MAC address. I can not find any way to remove the mac address. When I try to add the mac address to a blocked list, it says the said mac address can not be added because it is in the approved mac list. There has got to be away to remove the mac addresses with employees leave.