Hair colour

If you apply head and shoulders, leave it on half hour or more, it sometimes fades it, a bit, some colour comes out. If you just want it a little lighter, this may help, has worked for me.

You can also buy a colour remover, colour B4. Never dared use it. Safest to go to hairdresser!

You can use a dye remover such as ColourB4

I agree, see a hairdresser to talk about it.
Even a perm.dye fades though, with sun on it and regular washes.

It won't go lighter with a tint over a dark colour, the only way to lighten it is with bleach as in highlights. I'd go to a hairdresser to get it sorted professionally.