The pump is usually attached to the bottom of the washer fluid reservoir, and the best way to drain the system completely is to just remove the pump to drain the bottle and then spray the rest out of the tubes, but I have no idea how hard it is to access that on a 2012 Mazda 6.
I’m willing to bet that of you asked the Mazda dealer’s parts window guy for an “exploded view” drawing of the installation he’d be happy to print one for you.