Yes, with the schedule change creating an illegal connection, UA will make any reasonable reroute work for you *on UA metal* by opening award space (it will require the agent to ask a supervisor, but it will happen). I had a booking mistake cause a problem with an F FCO-FRA-IAD award, and they opened 2X FCO-IAD in F, which are never, ever available generally.

You want SYD-SFO nonstop, they will probably open it. You want to connect in LAX, but any particular LAX-SFO connection with your favorite seat available, they'll open it for you. You want two extra days in LAX, they'll make it work. Call with the flight numbers of the exact itinerary you want, and they'll make it work.