You can store baked ziti right in the casserole dish you baked it in. Just make sure it is completely cooled before refrigerating, and make sure to cover it airtight. Keep the dish refrigerated, and it should stay fresh for 3 to 5 days. Use a clean spoon to scoop out the desired amount each time you'd like to enjoy a serving. Reheat individual portions in a microwave or you can reheat larger portions in the casserole dish in the oven at 325° covered with aluminum foil. To reheat in the oven, it could take up to 20 minutes.