It is worth mentioning that this process can not be undone, though you can scale back the number or WAN ports, the application of the key permanently effects the Port setting options for the LAN network with using for VLANs
Image of Port Setting options before 5WAN key being applied
Image of Port Setting options after 5WAN key being applied
Notice that the "Port Type" & "VLAN" are now greyed out for LANs 1, 2 & 3.
Happy to Help,