Are they ornamental pears or fruit trees? If they are fruit trees, specific practices need to be followed and good clean tools are important.
If they are Bradford pears or many of the cultivars, I agree with skid & perfect, chainsaw to the ground, grind or remove the stump and plant something better suited and more sustainable in it's place. If you and your client feel it necessary to prune a pear tree, special attention should be used to make thinning cuts in areas where weak wood will develop. When the crotch angle of branching will lead to included bark, that should be pruned out early. Most cuts for this tree should be thinning cuts rather than heading back. Remove an entire branch rather than snip off the end which will lead to more canopy clutter.