Need serious help, want to go from red to medium blonde!

[smraquel]

So my hair is naturally an ashy medium-light blonde, like the first photo... I ve been coloring with Inoa 7.44 I think mixed with a bit of 7 to tone it down a bit as you can see in the second photo. And now I want to go back to an 8.1 so I can let my hair breath for a while. How should I go about it? (I usually use 10 vol cause my hair is really porous and thick) Will the 10 vol get me to the 8.1? Will I be able to completely remove the copper shade after I do it? HELP PLEASE!

(I cannot bleach it or try to strip the color off of it because my hair has been previously bleached (before the copper shade was applied) and it is really, really damaged and brittle. Please suggest a less agressive (even if it is slower and progressive) method)
Is there a way to do this without removing the existent hair color?
PHOTOS: http://s1279.photobucket.com/user/Raquel_Mendes/media/Untitled-1_zpsc9f38ad4.jpg.html

Thank you in advance for the patience to read this!

 

[AcidPerm]

If your hair is already coloured, you cannot make your hair go lighter without bleaching it.

If it's already damaged, you need to see a good colourist otherwise you risk damaging your hair further and it breaking off.