Play a game of "Stop and Go" with her. Start on the other side of the room, wait for a momentary lapse in screaming. Move toward her -- but each time she yells you turn-away-freeze. (So you are stopping with BAck towards her.) The next pause in screaming, you do the same. IF the room is small you can only take baby-steps.
So, it is the child's game of Stop and Go - but Yelling means Stop - and in this game your goal is to Reach Her via small baby steps.
Once you have achieved your goal you will give her preferred reward. (it can be scritches or praise IF she wants them-- or perhaps her favorite treat IF any chance that praise might not be enough)
IF she wants attention, this will work quickly.
From there, you can lengthen the gradually lengthen the quietness-time required by few seconds per attempt. Also a few repetitions of this and she should get the idea of quietness being needed.
So then, wait in another room until you Hear her Being Quiet, and come to reward her. (Have a treat already in-hand.) She will undoubtedly Yell the moment you appear, so then switch in to "Stop And Go" mode. (Saying "Are you being quiet? Are you? Quiet? etc as part of cuing.) Make sure you do this randomly, and NOT close-in-time to when you have heard her yelling. After approaching her via the Stop-n-Go game, provide the treat with Much Praise For Quietness. Then - back away out of the room (imagine she is the Royalty she knows herself to be) - so that she has your attention the Whole Time you are leaving the room as well. This is part of her Reward for her Quietness! (But do the back-away pretty quickly, so she will be occupied with her treat and will thus not break the quietness.)
IF she yells in such a way that you Need to Check on her, ONLY LOOK into the room. Do NOT approach any closer than needed to observe. Look around and IF all is well, say (in a Very Boring voice) "everything is OK," and Turn Your BACK and Walk away, closing the door or curtain behind you. So she will again learn that Yelling does not get her the Attention she wants.