If a flower wilts , can it revive itself?

there are flowers that will 'wilt' on purpose to save the water in their leaves from evaporating in the sunlight.... after the sun goes down, they 'un-wilt' and look just fine.... without any water from us..... it is a self protection thing...of course, if it doesn't perk back up after the sun goes down, THEN we know it needs water!!...