When objects are selected, holding shift, then selecting the objects to remove from the selection will work.
To 'get it back to the way [you] had it before'...I am not sure I understand. The alias 'R' is associated with the 'redraw' command...you could change that with 'aliasedit' and reassign the 'R' to 'remove from selection' i suppose.
If you have nothing selected and press 'r' you want a redraw, so changing the alias isn't a good idea. IMHO. But with items selected, the shift-select has worked for several years/versions. I haven't been on V2002 in >10 years, so I am not sure anymore.
Does that answer your question?