At SFO, there international UA flights depart from the international terminal. There is an RCC and F lounge in the international terminal, and a standard RCC in the domestic terminal.

If you are flying in international F (or PS coast-coast), you can use the international F lounge. In business class (or *G in Y) you can use the RCC, which in the case of an international flight from SFO would be most convenient to use the RCC in the international terminal.