Move marker right, or mmr, is just what it sounds like: you’re moving a stitch marker one stitch to the right. This often done to accommodate decreases in lace knitting.
To work a mmr, stop one stitch before your marker. Slip that stitch from your left-hand needle to your right-hand needle, remove the stitch marker, slip the stitch back from right-hand needle to left-hand needle, and place the marker on your right-hand needle. Your stitch marker will now be shifted one stitch to the right.