I would also recommend talking to an agent and seeing if they can split the reservation.

If they're unable to do it without reticketing everything (or you want to be extra safe), my second suggestion is asking once you arrive in LAX (via phone or at the counter) so the international (presumably) partner segment isn't a concern.

And if it's still not a working out, skipping the last segment is fine. I would tell an agent at the counter or gate so they're not calling for them. One off things are understandable and not something the airline will care about, especially with an award ticket where you're not saving money by booking a connection.