Wait at least two weeks after the final color. Red color very quickly loses its saturation. And that's a plus. After all, if he remained always bright, get rid of it would be even harder. The more time elapses since the last dyeing, the easier it will change the color of the hair.
If you plan to be repainted in black, you can safely apply paint. It will lay down smoothly, no hint of ginger will not. For all other colors will have to do a wash. This gentle lighting. Of course, you can choose a more aggressive methods, such as using concentrated peroxide. But since you can easily mess up your hair. Better to do twice a wash than fully clarified.
Independently carry out the procedure you are unlikely to succeed. The fact that the tool need only be applied over a colored portion of the hair. If it gets to the hair natural color, then you will have an uneven tone. Apply Blondirujushchy composition need quickly, carefully distributed over the entire length. If somewhere paint will fall unevenly, then the hair will be colored spots.
Perhaps the first time will not be enough. Then a week later repeat washes. When the red color disappears completely, apply the paint of another color. Do not forget that at first it will need to carefully spread over the regrowth, wait 15-20 minutes, and only then paint the rest of the length. This procedure is best to carry out several days after the wash, to avoid damage to the hair structure.