how to help speed up fading of permanent hair dye

hi girlies. i’ve been dying my hair dark brown (almost black) professionally for around a year now. i really want to go back to natural, but my hair holds onto color super well even though my natural color is lightish brown. my roots have grown in a few inches and i have some fading but the rest of my hair is sooo dark!! is there any way to make this process quicker without bleaching or chemically stripping my hair?