You can do it in Game Interface (Must have WC3 TFT)
But I wouldn't do it if I were you, it has side effects when I tried it (changes the names of the races on the menu even if you were out the game with the name changed races) It will also change the other players' wc3 menu to use your changed names. Its very annnoying and you takes a while to do something to get rid of it.
Yes, I know that change is functional but it will not work right away. As I said, that change takes a while to get into effect and then function properly.
Remember as I said at the beginning - it has side effects, so if this is REALLY needed, do so but if its not, leave it as it can get very annoying.
I changed my race names to blank. I cant tell whitch is whitch lol but i changed it back and there fine now but you gotta try it. Maby ill make a memmory game. Pick the human race to win. (lol)