I know they have hair color remover cause i used it one time on my hair yes i made my hair real dark that i looked like heck so i used it and than after i took that color out than i dyed it again with a lighter color
Dye it one or two shades lighter than the result you're trying to achieve. It will work. Use a 30 volume creme developer. Do not decolorate it with powder, otherwise you will end up with shitty and easy to break hair.
If you wan't to change your color by dyeing, it will disappear in a year, dyeing it lighter and lighter once at 2 months. You could decolorate it with powder and then color it again in what nuance you want, but you'll ruin your hair. Another method is going to a salon and they'll make you something just like the powder, but stronger, I don't know the English term, but again, your hair will need a lot of recovery and treatment.