LeapsofFaith

Hi guys, first time user. I'm working on a build I'm putting together, and I ran into what's potentially a noob issue. See, I'm trying to edit this piece to make it thinner however I can't seem to figure out what needs done to allow me to do this. Could someone point me in the right direction? The purpose is to incorporate the mechanics of a remote control's battery cover (the kind with a push tab of sorts), and I need the thicker end to be a bit thinner. panel.stl