[Kuuipo]

Bleaching will not remove it.
You need to buy two kits of colour remover kits-L'Oreal makes a great one.
Follow the directions. Then after all that, you will need to have your hair filled to make it ready to accept the new colour you will put on.
This is all best handled by a professional colourist.
I have gone from dyed blue black to platinum in the past for modeling assignments and have done it myself (I had a cosmetology lisence) but I preferred to have it done professionally because they have they can see the whole head better than I can and can add natural looking highlights.
Anything worth doing is worth doing correctly.