If you have existing self-governance policies in a policy snapshot, you can import them using the standard snapshot import process, with some minor adjustments.
Enable self-governance and sign on to the Policy Editor as the self-governance administrator.
You've imported a new Admin Point Governance branch and activated its self-governance policies. If you didn't delete the previous branch, you've also created a backup of the previous self-governance policies, which you can roll back to if needed.