the reduction function can be found in Polygons>reduce= option box
although its dosent do a very good job of mantaning the shape, you might have better luck reducing it yourself. I've found that it is mostly only good for making LOD (level of detail) models.
if your working on a budget you should probibly turn on the poly count HUD by going to "Display> heads up display = poly count". this displays various information about the model that is on the screen and what is selected (sub components, nurbs SubDs ect)
if you want to find information on the subject of polygon reduction a good place to start is the maya help file prss F1 and search Reduction and it should bring up information for you.