What is the legal way to declassify a document? The classification authority declares it unclassified. Who is the classification authority? The President has authority over all classified documents in the federal government.

If he says it’s unclassified, it is. It’s very simple.

Just because a document is marked does not mean it is classified. Most classified documents have a time limit, after that it’s unclassified, no one has to say anything or write a form or do anything.