It is always best to stay current with corporate formalities as described in §4.1 above. However, as the old saying goes, better late than never. You can hold a meeting where the shareholders or directors approve and ratify prior actions. This can also be done by preparing a Consent in Lieu of a Corporate Meeting. Either way, you must set forth the specific corporate action or actions you intend to ratify and approve.
Caution: If your limited liability protection is ever challenged because you have failed to comply with corporate formalities, this approach is better than doing nothing. However, it should not replace trying to keep current with corporate formalities.