It's very easy.
Turn off power to the rose, then remove the screws. If they were screwed tightly into wood, then replace them.
If they were screwed into wood but were loose, then fit larger screws.
If they weren't screwed into wood, then fit two Interset 'brolly' cavity fixings to secure the rose base.
Then reinstate everything and hang the new shade.
Turn off power to the rose, then remove the screws. If they were screwed tightly into wood, then replace them.
If they were screwed into wood but were loose, then fit larger screws.
If they weren't screwed into wood, then fit two Interset 'brolly' cavity fixings to secure the rose base.
Then reinstate everything and hang the new shade.