text: -- Revert default_changesets
  
  BEGIN;
  
    UPDATE changes
    SET changeset_id = NULL,
    delivered_by = NULL,
    delivered_at = NULL
    FROM changesets
    WHERE changes.changeset_id = changesets.id
    AND changesets.delivered_by = 'pre_changeset_change';
  
    DELETE FROM changesets
    WHERE delivered_by = 'pre_changeset_change';
  
  COMMIT;
  