Getting Hair Back to Natural Color?

I recently bleached and dyed my hair to an indigo color, but I was just offered a new job, very surprisingly, that requires me to dye it back to a natural color. My hair is naturally brown.

I've been trying to get the indigo out of my hair, and am wondering what my next steps would be. How light should it be before I use a box dye? Is there anything I should do prior to dyeing it with a box dye? Should I avoid a box dye altogether? Would it be better if I bleached it again prior it dyeing? Thank you!

By Gianna