A female saint later declared a demon?

I know there are some of the medieval (or earlier) saints that were 'dethroned' by the church as they realized that these were really nothing more than pre-Christian gods or goddesses turned into saints by the early monks to help convert the populace.

I have Never heard of any saint then being made a Demon, however.

Unlike one person's suggestion, Lilith has Never been recognized as a saint. If you know the name of the shop and its location, could you just get the phone number and call the owner up and ask?

A pope may acknowledge someone as a saint, but never as a demon

I never heard such a thing. Then again Catholics often have saints they don't venerate any more, like Little Hugh of Lincoln, who was allegedly killed by Jews, they stopped venerating him.

A saint is any person who has accepted Jesus Christ as Saviour. Neither the Pope or any human being can declare another to be or not be a saint. Read the Bible.

Are you talking about Lilith, Adam's first wife according to Hebrew myths? Or the greek, Lamia?

some would say joan of ark, but It would be helpful if you could at least get close on the name

I think many Christians suppose that Mary Magdalene was a prostitute.