You can disable HA from either device in the cluster. If disabled from the primary device, HA will be disabled on both devices. If disabled from the auxiliary, HA will not be disabled on the primary and will act as a stand-alone device.
After disabling HA, all the ports except the dedicated HA link port and peer administration port will be disabled for the auxiliary device. The peer HA link IP will be assigned the IP address assigned to the dedicated HA link port while the peer administration IP will be assigned the IP address assigned to the peer administration port.
When you disable HA, HTTPS and SSH continue to be allowed on the LAN and the DMZ zones.
After disabling HA, the primary device IP schema will not change.
If HA is disabled from a standalone device, the IP schema will not change.