I updated a save to the current build, bought a writ of exemption thinking it would be the same when you changed a slave to a peon like before, especially since the text was updated to now say subordinate, but the confirm button won't go through for a lack of better way to put it. I even made a fresh game and you can make your first companion a subordinate, but you cant use a Writ to make a slave into a subordinate. The "Lockridge" is from an imported save so that's why it's already used. The "Small" is from a brand new game so it's not, but clicking confirm does nothing, keyboard included. Tl;DR you can make a character a subordinate from the start, and likely from random even recruitment, as well as story characters, but they'll stay slaves if that's how you chose them at one point.