Can you K-Rend over K-Rend ? If so how please

Score it so it grips to it

You could use the micro gobetis primer to paint on then go over it .to be safe tho I would use the maitie base coat with the reinforcing mesh bedded into it then go over that , that would be safe as long as the original krend is safe and bonded well

You can red grit before hand prior redoing k rend

Yes you can you stick the beads down with HP12 basecote over the top of the old ones and apply a thin coat of top coat on first to slow the suction down, then apply the top coat