Reheating a fully cooked spiral ham is a straightforward process that anyone can master. Start by preheating your oven to 275°F and placing the ham in a roasting pan with a little bit of water. Cover the pan with foil to retain moisture. Allow the ham to heat for about 10-15 minutes per pound. Just remember, the goal is to warm your ham without drying it out, so keep an eye on it to ensure it doesn't overcook.