If you modify the configuration of an AP, those changes take effect immediately; you do not need to reboot he controller or the AP for the changes to affect the current running configuration. Certain commands, however, automatically force the AP radio to restart.
AP Settings Triggering a Radio Restart
Changing the following settings triggers the radio to restart on the AP-200 Series, AP-210 Series, AP-220 Series, or AP-270 Series access points. When the radio restarts, wireless services will be briefly interrupted. Clients will automatically reconnect to the network when the radio is again up and running.