The company that installed the granite countertops attached the dishwasher to the granite. I need to know how to remove the screws, without damaging the granite, in order to replace the dishwasher.
Unscrew the screws, using a screwdriver. There's no reason to think doing that will damage the granite. Almost certainly, the screws have been driven into plastic or lead inserts that are placed into holes drilled in the granite. Your new dishwasher may not have the mounting holes in exactly the same position, and will require similar inserts installed accordingly.