try to grep sys_mon, chip, chipr to find out who is currently occupying the CMS window. then use kill -9 and pkill -9 command to kill the process id. please be aware third party application are trying to gain control as well as other supervisor end user. So when killing these process, a new process will occupy the cms window in a glimse. And you need to kill several time such session and finally you are able to occupy the CMS window and turn the system to multiuser mode. So speed here is important.
Reboot server
Or
Stop, start CMS in cmssvc and change back to multiuser mode in su cms cms
