I used Bigen #47 it turned my hair black I want to go back to dark brown. I was told that I could use Bigen #45 and it would lighten my hair to dark brown without having to use
A color zapper. Does anyone know if this can be done?

Since you used a permanent black hair color, you will need to use a hair lightening product to lift the color a couple of shade lighter. You can use a 30-volume peroxide developer with your desired hair color in equal parts to achieve results. To avoid red/orange tones, choose a neutral or ash hair color.