Chemical hair dyes permanently alter the color of your hair. Once your hair is dyed, there is no way to "remove" the hair color to get it back to your natural color. If you have dyed your hair darker than you wanted it, though, there are ways to rid your hair of extra dye and fade the color a little bit. Either visit a hair care professional who can do a proper color correction or try some more subtle methods yourself.
See a professional colorist. Removing hair color from your hair is a complicated process and could damage your hair badly if it is not done correctly. Once the color is taken out, your hair will have to be re-dyed. Getting the new color mixed correctly with a base color, highlights and undertones is another process that requires intricate skill.
Wash your hair with original blue Dawn dishwashing liquid. Only do this once or twice and condition it well, because it is very drying. You will see some of the hair dye wash down the drain when you wash your dyed hair with Dawn.
Lighten your hair with hot oil hair treatments. Very few people know about this, but they can actually fade chemical haircolor. You can also use a homemade treatment such as olive, canola or sesame oil.
Sit in the sun. Use a sunscreen if you want to protect your skin, but leave your hair exposed. A few hours in the sun each day will help to lighten it and fade the dye from your hair.
Wait a few weeks to see if the color fades on its own. Very often, haircolor will be brighter and more noticeable right after you dye it. Within a few weeks it usually tones down to a less-obvious hue.
Use a clarifying shampoo or a dandruff shampoo. They help lift out extra color. Using them too often can be drying, so follow your shampoo rinse with a deep conditioner.
Purchase a really light-blond hair coloring kit if you are daring enough to experiment at home. It will turn your dark hair an orange color (or completely blond if you leave it on long enough). You can then put brown dye over it and your hair will be brown with reddish tones.
Do not use lemon juice to lighten dyed hair. Not only will you get uneven color (streaks), but you likely will also bring out orange, red and brassy tones. This will probably not lighten your hair to the color you want.