Frozen pies are pre-baked and ready to be re-heated. You may choose to have them thawed in the fridge so they are ready for a quick 20 minute re-heat in the oven or you can do it from frozen. It's entirely up to you. We like to have them ready in the fridge because it's quick and easy and they might turn out better.
From thawed: 20 minutes in the oven at 400˚ F (recommended)
From frozen: 35-40 minutes at 350˚ F
*Safe food handling practice is to re-heat until internal temp of 165 is reached.