rmmod <kernel module file *.ko>

[root@sylixos:/root]# help rmmod          
unregister a kernel module from system [DANGER! Not Safety].
rmmod [kernel module file *.ko]
[root@sylixos:/root]# 

[root@sylixos:/lib/modules]# rmmod usb64.ko
module /lib/modules/usb64.ko unregister ok.