Most cheat codes to change appearance tend to be things that force say bonus costumes to be unlocked, allow you to play as NPCs/bosses/secondary characters in some instances and maybe allow you to play as a costume from another part of the game (say a flashback). If the game allows some customisation of colours then that can also be an option.
If the game has something like that (beat the game and play as...) or is coded in such a way that you can play as a NCP (3d games tend to do this better than 2d games unless you have a partner or something throughout the game that has all the same animations) then we can try to look at character selection cheats.
If not then chances are you want a ROM hack to either copy across the data (or maybe copy the translation you want to whatever version has the character you want) or remake it.