Give the wood a decent sanding down first of all. If in good condition already, use a 80 grit sandpaper, otherwise use a 60 grit. Fill any inperfections with wood filler and rub that down until smooth. Then apply acrylic primer undercoat, giving it as many coats as needed to cover the navy gloss. Then a quick sanding again using very fine sandpaper like 180 grit and finally apply the eggshell making sure you don't get runs! Hope this helps and good luck!