Reheating red meat is tough. Knowing this, my first preference is to overeat a little and finish any leftovers during the meal if possible, because I know it won't be as good later. However, if you do have leftovers, there are preferred ways to reheat. I do NOT recommend the microwave under any circumstances, even at half power. It so often turns gnarly and stinky. I recommend wrapping in foil and heating in a 250F oven for about 15 minutes, or until warm enough to eat. You can also warm it in a skillet but you are more likely to lose any redness in the center because of the direct heat.