I don’t think there will ever be permission. If it comes to it, you prepare for consequences and do it.
There wont be permission given.
The right wil have to be exerted and defended.
If the side leaving has good and just reasons for it, I believe that spiritually that gives them a major advantage. Its why the first major attempt to leave failed. I believe the south may have won if they weren’t so dogmatically stuck on demanding slavery continue.