The suggestion would be do both: order new tile and remove the
tile, especially if the wall tile is only rated for wall and not for floor (https://www.builddirect.com/learning-center/flooring/porcelain-tile-rated-hardness).
hope
this helps

We are removing the tile they put on the floor and replacing that with floor tile. The question is whether the tile that originally put in the wrong place, could be reused for the wall.

it depends on the thin-set they used and how long it has set, furthermore, what type of tile. if the tile is thin, then no it would not be suggested, but if is thicker, then make sure all the thin set is scraped off to avoid lippage. However, given the fact that the tile is rated for wall only (if it is), then the suggestion to reuse would not be recommended, unless it was removed quickly. hope that answers your question.

OK, thanks. It is marble tile, if that makes a difference. The removal was in 24 hours. I will ask what type of thin set they used....