I had to do this recently with my new turbo. Was told to loosen the 6 bolts that hold on the 2 plates in the pic, 1 being where to attach the RS500/original damper, then just rotate the exhaust housing to whatever orientation your exhaust manifold is.

As far as I know, it's the same procedure for the compressor housing, loosen the 6 bolts, rotate and tighten the 6 bolts.

Hopefully someone else can clarify as never did this before.

Philip.