That's a tough one, Michael. I don't know of any way to remove a gloss coat, that won't also remove the paint underneath. Except in the case of Future, which can be removed by a weak ammonia solution, like Windex; if the gloss coat you're working with is also acrylic, then that might work, but if the paint underneath is also acrylic, then the solution could attack the paint. If it's acrylic over enamel, it might be possible to remove the gloss coat without harming the paint underneath.
If the figure was originally in a matte finish, and you've gloss-coated it, could you instead hit it with a matte lacquer, like Testor's DullCote?
Prost!
Brad