http://docs.aerohive.com/330000/docs/help/english/ng/Content/reference/understanding-aerohive-ap-client-mode.htm?Highlight=client%20mode
To enable it on the AP you need to either create a device template (if you're using it for multiple APs), or on a single AP you can go to monitor > click the AP > interface settings > WiFi0/1 > select client mode
