public void removeDirectPresence(JID ownerJID, JID recipientJID) {
        if (recipientJID == null) {
            return;
        }
        Collection<DirectedPresence> directedPresences = directedPresencesCache.get(ownerJID.toString());
        if (directedPresences != null) {
            String recipient = recipientJID.toBareJID();
            for (DirectedPresence directedPresence : directedPresences) {
                directedPresence.removeReceiver(recipient);
            }
        }
    }
Sends an unavailable presence to the entities that sent a directed (available) presence
to other entities.

@param update the unavailable presence sent by the user.
xmppserver/src/main/java/org/jivesoftware/openfire/handler/PresenceUpdateHandler.java