1. Check that the cab actually allows it, most cabs do. My mvs cabs have the hardware to rotate, not sure about candies. If not its a skillsaw hack job
2. Undo mounting hardware and carefully rotate, its probably a good idea to dis everything, remember to discharge the crt if you do.
Also rotate the crt the correct way to avoid further stuffing around.You dont want an upside down/back to front pic. The jamma boardset may have dips for this anyway.
3. Consider the mvs-jamma connection issues before plugging in your Raiden board.