I'm assuming you are talking about swapping positions of the two buttons. I'm sure there are other ways of doing this but that is one of the Many options that you have in GravityBox. You'll have to be rooted, have Xposed Framework installed and if I remember right an updated version of busybox installed.
I understand the proceedings to install the Xposed Framework and Gravity box but I'm not sure about busybox.
I've just followed the through with the installation without 'busybox' and everything seems to work fine. Thanks very much guys