Switch off your sander's power, and then disconnect its power cord from any outlet into which it may be plugged. Put on a pair of cloth gloves.
Secure the sander's abrasive pad with one hand. Use a flat-head screwdriver to remove the screw from the center of the pad. Remove the screw and its washer, and then remove the abrasive pad. Set each disassembled component aside for safekeeping.
Use a Phillips screwdriver to remove the six screws from the circumference of the sander head. Set the screws aside with the other disassembled components. Replace any of the parts as needed.