color fix and highlights??

hi everyone, this may be a dumb ques b/c i know bleach strips the hair, but what would color fix do to highlights, if anything???  going back to brown and have high (lots of em) and lowlights in now and want to take out the low color so i can get the new color as fresh as possible, if this makes sense.  just wondering if there will be any effect on the highlights, thanks!!!