Turn the lazy Susan upside-down on a work surface.
Look through the access hole in the base as you slowly spin it. Stop when you see a screw holding the top onto the ball bearing plate.
Remove the screw through the access hole.
Continue spinning the base and removing screws until the top of the lazy Susan detaches from the ball bearing plate.
Unscrew the ball bearing plate from the base and discard it.
Screw a new ball bearing plate to the base. It should be the same size and shape as the original, with holes that line up with those already in the base.
Place the base onto the top. Line up the screw holes with the holes in the ball bearing plate. You will have to look through the access hole to do this. Line up the edges of the top and base, then gradually lift and rotate the base until the holes line up.
Screw the ball bearing plate to the top, spinning the base to access each screw hole through the access hole.