You have to use a set chip to access the setup menu where you can change the game variation. Latest one that I know of is the Set Chip 6.03.10. There are two chips on a riser board, plug them onto the white connector next to your eeproms while the game is powered off. Turn game on and you'll be in the setchip menu.
There's a bit more to it than that, and you'll have to know what your game is (multi-line, Cashman, any ante bet, etc.) as well as your max bet. Sun and Moon is pretty popular, and that's a standard multi-line game, so it's pretty easy to set up. If you use the same set chip that the game was last ram cleared with, all of your settings will stay and you can then just change the variation. Otherwise you'll have to start from scratch.