change username/password takes no effect for 802.1x wifi clients

I'm running a freeradius to authorize user access on wifi network(EAP). everything works well, I input my username and password I can then login via 802.1x then surf. However if I change the username/password in mods-config/files/authorize, then restart radiusd, I can still surf the internet using the old username/password, no relogin required, until I logoff the wifi network, and relogin again, now I need supply the new username/password. How to force a re-login(via 802.1x) whenever I change username/password in freeradius? Is there a way to do it on freeradius side, or I just restart wifi network whenever I restart radiusd? Thanks,