Should be a straight swap, just need a rear hub with the same spacing.

Masi doesn't list that spec but I'm guessing it's 135mm rear spacing. There should be lots of options out there. If you can't find one (which I doubt), you can easily find someone to lace a 135mm hub to a 650b rim for a reasonable cost. >$500.

Shouldn't need to change components unless you go to a bigger cassette.