Huh?
No...you don't need to secede, or have your Duke change allegiance, to take your region and leave the realm. Every region lord can join another duchy at any time.
Also, barring temporary situations between position loss and appointment, every Lord has a Duke, always. There are no Imperial or duchyless regions anymore.
I was relating it to the idea of a secession. You need a Duke to secede. And by "need a duke" I mean, "need a duke on your side" to do it.
But this is off-topic anyway, so I'll just drop it.
