If it's like every other Yamaha I remember, push the flipper and get hold of the cable next to the plastic block the cable runs through with needle nose so you can slack the cable to unhook it from the back of the flipper. Once unhooked from the flipper, it can be taken out of the block and moved to the other side and reinstalled. Be careful not to crush the cable. Just squeeze it enough to hold it and get some slack in it to unhook it from the flipper.
Once you get some slack in it you'll see how it has to be manipulated at the back of the flipper to release the cable stop from the stop detent.
It can be a little tricky, but once you slack the cable to see how the cable stop disengages from the detent, it'll seam easy.