Playing in a heart contract, South as declarer, leads ♦2 from dummy. East ruffs with ♥J (revoke), South follows, and West discards his ♣6. East now leads his ♦5 and partner over-ruffs declarer with ♥9. South remarks to East that he revoked on the previous trick (trick 12).
Director!
The Director states that since the (established) revoke occurred on the twelfth trick, there is no automatic adjustment – Law 64B6. But the trick must still be corrected. So he rules that East must retract the ♥J; South must still follow with ♦Q; and West is allowed to ruff with his ♥9. East will then make the last trick with his boss ♥J; so declarer still loses the last two tricks (which he would have lost anyway without the revoke).