1) Turn off a cold and a hot water supply.
2) Unscrew or loosen a bolt which fixes the handle to the cartridge rod using a hexagon.
3) Remove the handle from the headworks rod.
4) Carefully unscrew a decorative ring by hand without using any tools.
5) Remove the defective headworks from a body of a mixer.
6) Insert a new hradworks (for hot or cold water) in the body of a mixer.
7) Assemble the mixer.