ssh into your kncminer if you know its IP address is 192.168.1.X:
ssh -l root 192.168.1.X
screen -d -r
q
wget http://ck.kolivas.org/apps/cgminer/kncminer/cgminer
chmod +x cgminer
./cgminer -c /config/cgminer.conf
q is to quit the already running cgminer
Note also that this is perfectly safe and only saves the cgminer binary to the ramdisk which means that if you have any issues or reboot it will just go back to the usual cgminer built in. It is also compatible with any of the kncminer firmwares, though I find 0.96.1 to be the best for me.