Another way to implement this concept is to understand the max-loss concept. Lets say even if one was to simply move the stop loss to -0.8R after setting up a 1R trade.
In that case, the max loss one is willing to take is -0.8R and the if profit, it is 3R
Even though this seems like that we are simply tightening the stop loss, but over a large sample of trades, you'll loose less - thereby increasing your overall risk:reward.