I’m sorry but that is not possible. You didn’t specify the version, nor the used workflow for the responsive project. If you did use Fluid Boxes, I don’t see a direct solution. The theme which includes the used master slides and styles are different from the theme for a non-responsive project. If you used Breakpoint views, you could create a new project with the same size as the primary view and try to copy/paste the slides to that blank project.