There is apparently no such thing as a "Saver Award" in Business on UA's website anymore. It's been replaced with a new category called "Business/First (lowest)". Nonetheless, I checked every conceivable date for UA domestic Business class partner awards on Miles & More, and they simply don't exist. Not sure why they advertise that you can book them on their website. You most definitely cannot. They either have zero availability for most dates (all classes), or they only have economy flights.