You can reheat leftovers in a sauté pan or skillet set over low heat. Cover the pan to keep moisture in, and give it a gentle stir every few minutes to help the pasta heat evenly. I also like to add an extra splash of broth and and extra splash of cream to the pan as well, because the pasta does absorb some of the moisture in the fridge. Alternatively, you can microwave leftovers on 50% power for 1 minute at a time, stirring in between, until heated through. If you've made just the sauce ahead of time as I recommended in the previous question, you can easily reheat it in a small saucepan set over low heat. Just don't forget to whisk frequently to avoid burning the bottom!