I am planning on making a pie for my dad for father's day. I know when you buy most pies at the grocery store, you have to pop it in the oven for a few minutes to heat it up. Is it possible to do a similar thing with a homemade pie - bake the whole pie (not just the crust) most of the way one day, and then finish it off the next? I don't want to fully bake it and then heat it in the oven because I am afraid it will burn or overbake, but I also don't want to underbake it and have it go bad.
The butter or shortening should never slowly become warm between the time the crust is mixed to the time the time the pie is finished baking. This is why you use iced water and cold shortening to mix the crust and place the crust after rolling back into the fridge before filling.
Imagine the example of bread. If you have uncooked bread dough and pour water on top of it the water will run down the side and if the water sits in the bowl with the dough only a little will be absorbed into the raw dough. Now if the bread dough is cooked and water is poured onto it the bread will absorb all the water. The same concept is true for pie dough that is about to be frozen. The uncooked dough will repel the moister better than partially cooked or fully cooked dough.
Also if the dough is fully covers the filling, the dough has a lot of fat in it which acts like a layer of protection in the freezer. Freezing pies is great at the height of berry season when they can be bought in bulk super cheap to preserve the fruit for when it's cold.
I doubt that if the pie filling is super runny it's a good idea to freeze it, otherwise just having uncooked dough works quite well for freezing pies for later.
You didn't mention which type of pie you would be freezing, so all I can offer is what I do. Apple pie can be frozen before or after baking; I prefer after, and if you sprinkle some turbinado sugar on it before you bake it, it will keep a nice, crispy top crust after the thaw and second bake.
For me, berry pies are best frozen after baking. Use tapioca starch in your filling instead of cornstarch, and it won't turn runny on the second bake.
Meat pies are best frozen before baking if they are just meat pies. If they contain potato, either pre-cook the potato before it goes into the pie, or bake before freezing, because uncooked potato will either disintegrate or assume a very peculiar, spongy texture.
Fish pies I recommend baking the crust before filling, and then freeze it without baking the filling. I learned the hard way to only cook the filling once, so it goes into the baked shell unprocessed; a second bake of the filling usually creates a truly spectacular (and fishy-smelly) mess for me, and it takes days, plus sometimes a wall-washing, to get the smell out of my kitchen.
Quiches, cream pies and pies involving curd or custard, do not freeze at all. They either disintegrate or they adopt a grainy, unpleasant texture and lose most of their taste.