Let it slowly rot in daycare for all of eternity. In all seriousness, depending on what game your playing, there could be a glitch to erase it. if not, trade it to someone else, erase your save file, or if you're playing on a 3ds/2ds, transfer it to Pokemon bank. The only other way is a cheating device. (Unlike some people, I have an action replay dsi, and I love using it.) Hope this helps!