There are aftermarket solutions available for modifying minivans to incorporate swivel seats. These modifications are typically carried out by automotive accessibility modification companies or specialists who can customize the minivan to meet the specific accessibility needs of individuals. If you are interested in having swivel seats installed in a minivan, it's recommended to consult with automotive accessibility modification companies or experts in your area. They can assess your requirements, provide information on available options, and guide you through the process of modifying a minivan to incorporate swivel seats.