Walls and Ceilings - drywall taping over gloss

We hung new drywall in a bathroom and had someone help with the taping. He primed it and put on a coat of oil based enamel (gloss) and now we see quite a few areas of the taping that need to be touched up. Not a big deal but not sure if the mud will adhere to the gloss finish or do we need to sand it down. Also, once the mud has been sanded and primed again can we paint over this with a satin/eggshell type finish or does the whole room need to be sanded. We want the best finished room we can get and fear that the gloss finish is just showing too many imperfections. Any guidance would be great.

You need to sand then wipe with a deglosser [will soften the paint and promote adhesion] before coating with mud. If you use an oilbase satin paint you just need to prime the patched areas. If you want to use latex you must sand all the paint and prime with a good oilbase primer first.