The opening scene shows a ball rolling across the lawn of a fairly large house in the woods. The house has no inhabitants and is furnished as if they might have just left. A rag-tag group follows the ball into the house. They soon become suave and sophisticated persons who interact with one another as at a cocktail party. Finally, the people revert to their former selves and leave the house. It’s in color. I obtained this movie at my local library several years ago. I’m guessing that it’s 20-30 years old.
Savages. https://366weirdmovies.com/apocrypha-candidate-savages-1972/
“Savages” 1972 is correct. Many thanks to irtmadmin.
Glad to help!