If you have black hair, how do u dye it brown again?:)

If you want to go from black to brown, you will need to use some kind of hair lightening product. It's best to have your hair pre-lightened to a level that is lighter than the color you want and then apply the desired color. Another option is to use a (cool) base ash hair color and a 20-volume peroxide developer in equal parts to achieve results. Ash hair colors work best on dark/black hair. It will cut down the reddish tones and give you a brownish color.