From what I’m learning currently, the best approach is in writing (letters), and the process itself is known as reconveyance/conveyance. That is to move out of the maritime jurisdiction back to the land/soil jurisdiction. Once you notice the relevant GovCorp, Crown, and Vatican entities they become obliged to correct your status on ‘their’ records.
For further information visit Terra Australis States Assemblies and or The American States Assemblies websites.
Additionally, look up Anna Von Reitz.
Also look in the SE webinars section for the two sessions with Muki.
And yes, a great many people have done this, especially in America.