Does anyone know what happens if you connect to the internet on two different Pokemon games?

have Y version and I have quite a few friends on my 3DS, however, my friend is using my 3DS and really wants to connect to the internet with X version so she can get a Japanese ditto…My question is what will happen? Will it rewrite everyone of my friends to have her as a friend instead of me or does it just have both people on the friends list now? I don’t want her ruining anything so I’m not letting her connect but I’m just wondering.