I have gone through this at least twice.I had black hair,and NO you cannot "DYE" it back to blonde. I hate to tell you this,but you absolutely will have to bleach it if you want it blonde again. If you dont bleach it,it will probably turn an odd orange/red color but will not be blonde. I had to bleach mine twice,and it was yellow on top and orange on the bottom~I went to 5 salons and no one would touch me. So I used an ASH color to get rid of the orange...but my hair was fried beyond belief. Please,I beg of you! Dont make my same mistake,salons can get you where you want to go with less damage and heartache. I'm all for coloring at home,but when you are trying to do something this tricky,it's best left to professionals.