IBM has CDE documentation for AIX.
This bit is interesting:
Stopping the Common Desktop Environment manually
When you manually stop the Login Manager, all X Servers and desktop sessions
that the Login Manager started are stopped.
Open a terminal emulator window, and log in as root.
Obtain the process ID of the Login Manager by typing the following:
cat /var/dt/Xpid
Stop the Login Manager by typing:
kill -term process_id
Typing kill -term 508 kills my session and logs me out to the command prompt.
