Aim a heat gun/air dryer (on high) at it, but be cautious not to damage the surrounding areas. Promptly after the heat being used, try grazing a new razor blade over the assumed edge of the decal. if it catches it, carefully use the razor to coach that edge away from the painted surface. apply some wd-40 over the decal, let it soak, but not dry, for a few minutes & try lifting it up more.