Need advice-want to change haircolor

Hi everyone, I've been coloring my hair (to cover a lot of gray!) for 6 now. I've been using Miss Clairol in Cinnamon, and the color has worked really well for me, but frankly I'm getting tired of it. I'd like to go back to my natural color, med. brown with a bit of warmth, not ashy or neutral. How can I do this successfully with the least amount of damage? My hair is somewhat dry from the coloring, but I do think it's in good enough condition to take it. I am thinking of Revlon Colorstay in Med. Brown, or Clairol Hydrience in Mocha Splash.