1. Pour the soup into a medium pot over medium-low heat. Fill the empty soup can with water and set aside.
2. Add the pinto beans, followed by the can of water, to a blender and blend on high speed until smooth.
3. Pour the blended beans into the pot and stir.
4. Stir in potato flakes one teaspoon at a time until soup reaches desired thickness. Season with salt and black pepper. Heat through until ready to serve.