Superior Will: If you are dazed or stunned, you can make a saving throw at the start of your turn to end that effect, even if the effect doesn’t normally end on a save.
Unnatural Vitality: When you drop to 0 hit points or fewer and are subjected to the dying condition, you can choose to be dazed, instead of falling unconscious. You make death saving throws as normal, and if you fail one, you fall unconscious instead of being dazed.
Can a revenant use the SW feature to get rid of the daze effect from UV? Normally I'd say yes, since the daze effect certainly is one that "doesn't normally end on a save", but in this case you'd still be below 0 hp.