Unplug the power cord of the Skil plunge router from the power source before attempting to change the drill bit. Turn the router upside down and set it on its top on a flat surface.
Remove the chip shield by unfastening the screws with a screwdriver and lifting the shield off the router. Lock the collet in place by pressing down on it and turning the chuck assembly counterclockwise.
Loosen the collet chuck assembly by turning it counterclockwise until the drill bit is free and remove the bit from the router. Place the shank of the new drill bit into the collet chuck assembly and tighten the collet nut around the shank using a collet wrench to turn the assembly clockwise.
Tighten the assembly with the collet wrench until the drill bit is secure and attach the chip shield to the bottom of the router with the screws. Turn the Skil plunge router over on its base and plug the power cord into the electrical outlet.