The entire state of California would have to secede first. Then parts of it that want to from independent territories would have to petition the US congress for admission. I doubt Sacramento would allow sections to break off. In any event a long process.
Agreed it could be a long process. But I don’t think Richmond had much influence in the creation of West Virginia.
My question is.. how many divisions can Sacramento muster up to stop those regions from breaking from CA, especially if a friendly USG is in the mood to help?