Takes 5 minutes. The legislature puts it up for a vote.
That’s a quick process.
I guess the actual vote would be preceded by politicians/ activists trying to explain Secession to the public.
Some would justify it, while others would say it would be the worst possible choice for this nation.
Victory goes to the best explainer with the most money behind him.
There will be no secession. Not a single state legislature willing to take that up. Such things would only happen on empty bellies. We are way too fat and content for that.