Implications if 'Private' Succession Plan Administrator Leaves the Organization

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Our team is preparing to launch Succession.  In considering the use of ‘private’ succession plans, what actions would need to be taken if the person who created the private plan (the default Administrator) were to leave the Company?

If no other admins were added to this private plan, would the plan become 'abandoned' or would the data still be accessible?

Has anyone had an experience with this or have any recommended best practices?