User blog comment:B214/Question and Answers 3/@comment-24098614-20140829220850/@comment-73.178.133.185-20140912011309

Who says that she lost her status? Assuming that there are no special rules for the children of the 72 Pillars to be officiallly recognized as High-class Devils in the first place, then the only reasons she wouldn't receive her Evil Pieces to start a Peerage would be either that she chose to decline them or her father chose not to hand them over (if I recall correctly, Lord Gremory was the one who handed over them when Rias came of age). Even if she has received them, it doesn't mean that she has to use them. On the other hand, just because on is a servant, doesn't mean one can't have there own Peerage. Take Tannin, for example. He is still considered Mephisto Pheles's [Queen] even though he has his own Peerage.

But as B214 said, there has been no official information from Ishibumi about this particular issue. In fact, there is no mention on whether Ravel is actually considered a High-class Devil or not. (IPersonally, I'm more interested in rank/level of Sairaorg's Peerage, some of whom are from "fallen" Houses).