I am making a large New Year's dinner and am making as much as I can ahead of time. I cooked the turkey today and put the breast meat unsliced in the freezer.
I add a little water to my leftover turkey and seal it well before warming up. Or you might try heating it up in canned chicken broth or adding a bouillon cube to the water, but I didn't need either and the turkey flavor was still tasty.
My dad always reheats his turkey in chicken broth in the oven, seal the pan. It comes out great. And he got this from chefs that worked in nationally renown restaurants, where he also worked. So it is sound advice.
I've heard that the chef's trick is to wrap it in lettuce leaves to reheat.