"Can my run-flat tires be replaced with regular tires without buying new wheels, and would my local installer have the special knowledge or equipment required to do it?"
Yes, you can use a non run-flat tire; they will work well on your stock wheels. Make sure you have a Plan B in place if you do have a flat tire, as many times no spare tire is available from the factory in vehicles originally equipped with run-flat tires.
There are two options available. Either carry a spare tire, a full-size spare, space saver spare, or if you have a winter/summer set of tires and wheels carry one from the off-season (temporary use only!) in your trunk. The second option is to have a product like the ContiComforKit from Continental in your vehicle. This product is an air compressor with a tire sealant inside that can be used to temporarily fix small punctures.
Most of Tire Rack's independent Recommended Installers will have the equipment necessary to handle installation.