Well, I believe I had this working once in an old project using Andorra .4.5.0, but with the latest Andorra version, at least, the following code doesn't work:
[pascal]
AdDraw.Finalize;
with AdDraw.Display do
begin
Width := 640;
Height := 480;
BitDepth := ad32Bit;
DisplayMode := dmFullscreen;
end;
AdDraw.Initialize;
[/pascal]
It kills the display (redrawing the last frame before AdDraw.Finalize).

Checked the docs and FAQ, but couldn't find anything on this. (And if you're wondering, the SF forums for Andorra seem as dead as this subforum... I might repost this there though)