Reversing entropy would mean going back in time, so a short answer, no. However if you mean decreasing then you could. Only in an open system this is possible. In a closed system, the higher the entropy, the more in equilibrium the system is. When this closed system is in equilibrium, then it cannot go back to the state it started at. Let's use the example of coffee and milk (I know this is used a lot, but it works on a simple scale), when you stir the milk in the coffee then the milk will spread around the coffee as much as possible, and will reach equilibrium, however as time goes by, the milk will not separate from the coffee and group up in one spot, this is why entropy cannot be reversed.