The old rule was that, if you hit a return that was in, but then corrected your out call, then you replayed the point.
The new rule is that if you call a ball out, then realize it was in, you give up the point immediately. It doesn't matter if you returned it. As soon as you called it out, the point was over. If you were wrong and admit it, you lose the point.
Don't let that stop you from correcting your bad out calls. I've had to do this a few times.