Hair coloring virgin dark hair

This is a tough one in my experience because the process of coloring hair extensions from when you buy them is not the same as how we color our hair on our head. So dying blonde colors darker is easy but going from a darker color to a lighter color can be more difficult as most hair extension companies go through a number of chemical process to lighten with (from my understanding) more of a fabric dye rather than bleach or lightner like we use on our hair in the salon. Thus keeping the extension hair in much better condition. However nothing is impossible. Really its about getting a mild lightner or a very mild bleach say a 10 vol developer and watching it very close. As soon as you see your color come through perfect if it goes to orange or to light you can always dye darker with the right color of your choice.
I have never used box dyes from the store on extensions have heard a few people complain about hair turning very weird colors though. You can also take a small piece and try toning it to see if it would lift it enough to your color it seems your only looking to lift one to two levels so that may be a thing to try. If that doesn't work try a box dye of your choice on a small piece and see how it goes. Being that the hair (claims) virgin it may take to a box dye better than stories ive heard.
Different processed hair will react different to color change so its kind of a gamble of what works for you. Keep trying small pieces till you find what you like.
Im always skeptical of (virgin) hair online since there has to be some kind of chemical process the hair goes through to be sold from a company. Its not like your sister cutting off her hair after she grew it all out and handing it to you. Just make sure your getting what you pay for.  Best of luck to you and let us know how it goes.