With great care! i'm assuming you want to lower it? this requires accurate measuring of the saddle (usually at three different points) when it is fitted to the guitar and again when it is removed so that you may remove (grind off) the required amount of material, the real problem is that acoustics can tend to 'belly up' slightly around the bridge area, which means the saddle would need to be ground with a slight arch to it otherwise it won't sit flush in the bridge, basically if you don't know what your doing, take it to a tech.
Strat totin
Six string slingin
Son of a gun
I met my maker, i made him cry, and on my shoulder he asked me why, his people won't fly thru the storm, i said, listen here man they don't even know your born.
strat-man rocks with vox