I’ve recently re-painted two rooms in my house. In both cases I used a satin finish on the walls, flat on the ceiling. The finished job exceeded my expectations – the cut-in at the ceiling is sharp, all trim caulked, the color is dead on – really looks nice. Only problem is the wall finish is a little too glossy for my liking and in retrospect I probably should have went with an eggshell.
Is there anything I can do to dull the surface finish of the walls without having to re-paint?
There is no way that I'm aware of to change the paint sheen without using a different paint. It is possible that the paint needs some time to cure and tone down to its true sheen, many paints are really shiny when first applied.
Give it some time, most paints take up to 30 days to cure.