The first thing to consider is why you would change a plug. Electrical appliances that are old, poorly wired or broken can be a danger and a fire risk. The things to look out for are warm or hot plugs, scorch marks around the plug, fuses that often blow out or flickering lights. Badly wired plugs with loose wires or wires sticking out of the plug.
These are all signs that something is wrong with your appliance and it may be worth changing the plug.
Step 1: Unscrew the Phillips head screw in the centre of the plug, beneath the 3 pins. And remove the cover of the plug to expose the wires.
Step 2: Take a screwdriver and remove the 3 screws that attach the wires to the plug. Then remove the wires from the plug. This should completely separate the original plug and the wires. You can now get rid of the original plug.
Step 3: Take the new plug and remove the back and place it with the pins down on a table so the back is exposed. Then place the BLUE wire in the left side fixing and tighten the screw. Take the YELLOW & GREEN wire and place it in the centre position (at the top) and tighten the screw. Now take the BROWN wire anyplace it in the right hand position and tighten the screw.
Step 4: Now replace the cover for the plug and tighten the screws.
Thats it, your new plug should work!