Why is notifying the attorney not optional?
Because a third party who does not know about the revocation has no reason to refuse the document. A bank presented with a notarised POA that appears valid will act on it, and unwinding that afterwards is a dispute rather than an administrative correction.
Notice is what converts a private decision into something the outside world can rely on.
- Notify the attorney directly and keep proof of it
- Notify banks, registries and any counterparty relying on the POA
- Keep the notarised revocation with the proof of notice
- Recover the original document from the attorney where you can