Any leftover lasagna rolls can be stored in the refrigerator, in an airtight container, for up to 3-5 days. It is also possible to freeze any leftover rotolo for about 2-3 months.  Keep in mind that the cream sauce might separate a bit during the freezing and thawing process. This will alter the texture a bit upon reheating, but it is perfectly safe to eat.  Once ready to reheat, pop your leftovers into a 350 degrees F oven for about 25-30 minutes from thawed, or 40-45 minutes if frozen.