My hair is naturally very dark brown, I dyed it a dark red. Now after about 4 month it is a dark reddish brown and I want to know if I can dye it a light ash brown or do I have to wait until my hair fully grows out (short hair).

No.

Haircolors "add" to each other. It's not like painting a wall. Also, lighter dyes won't lighten the artificial pigment that darker dyes put into the hair.

You'll need to remove the artificial pigment first. There are many color removers on the market: ColorFix, Color Oops, Color Zap, Igora Phantom, etc. Once you've removed the artificial pigment, you can proceed to dye it the color you want.

I have dyed my hair to blond it came out orange then put I light brown on it now its ginner I want to do blond