How to remove a orphaned user in Ubuntu?

Hello. I have AcuCOBOL in Ubuntu, using AcuThin to connect to the server from Windows PCs. Sometimes energy goes wrong and shut downs wifi routers, so users disconnect from the server, and leave the licenses "in use" (socket connecton error). I want to remove these orphaned users from the session without restart the server. If you ask why I'm asking for this, I'm the new sysadmin of my enterprise, but because the last one got fired, I'm clueless about how to use and maintain this software, because the last sysadmin left no manual, neither documentation. I will be very grateful to anyone who can help me.