Dark brown to Light Ash Brown Hair?

My hair is colored with dark chocolate brown level 4. My ends are a little darker than my mid shaft/roots.

I want to have light ash brown/dark blonde shade. How do I do this at home? Do I use color remover or go straight for bleach?

If so what level developer for the bleach, how long do I leave it on? Do I need to tone hair after bleach or just add the color of light ash brown I want?