The definition of an Autonomous Region means that it is separate government from the national gov. and functions mainly on its own.
A state, like Alaska or Texas, is not considered an Autonomous territory, so cannot vote on secession.
They must be able to govern themselves as if they were a separate national entity.
In these cases, like Venice, Flanders, Catalonia, etc. They should be allowed to declare themselves independent after holding a referendum achieving a 2/3 majority vote.
Such an entity should then be disallowed from joining to become a part of another national entity for a period of at least 10 year.
These people have a right to "becomes necessary for one people to dissolve the political bands which have connected them with another" and achieve an equal station.