Why would you want to do that? Depending on the model you'd end up with negative bounce. IMHO bending lofts should primarily (only?) be done for gapping purposes. Ball flight or spin should be fixed in another way (different model iron, ball and/or delivery conditions). Arguably you can weaken an iron more than a few degrees without too much trouble as long as the leading edge doesn't rise too much, but strengthening a thin soled blade quickly gets you into a digging nightmare.