Yes. Open the drain on the radiator, and that will get about half of the coolant out of the system. Add until full, start the engine, and drain it 1 or 2 times more to remove most of the old coolant.
If you truly are flushing the system, you'll need an open port for the incoming water, and an outlet port for the outgoing water. The radiator drain won't handle garden hose volume, though.
If you truly are flushing the system, you'll need an open port for the incoming water, and an outlet port for the outgoing water. The radiator drain won't handle garden hose volume, though.