

> Beneath autonomy, there should (i am not sure of DLC requirements but may require "Art of War" or "Common Sense") be a button to release their core land at a cost of -10 prestiege. > In your 'own' diplomacy screen, release a vassal, it should be the bottomost option, you'll have the option to release them & to play as them (which is compatible with ironman)

There are two ways, both require you owning the land mecklenburg is on however and mecklenburg having a core on that province that is not expired.
