A user was logged in via XRDP and the screen locked. Each attempt to logon also resulted in a locked screen. Rebooting is not an option. There needed to be a way to identify the user and forcibly log them off, and there is.
Logged on as root and typing the who command lists users and logons. A great working response is to use ps to identify the user, for example pts/1 (it may be some other value pts/2, pts/3, etc.) Then use the kill command to kill the process that was identified with the ps command.
ps -dN | grep pts/1 kill -9