Use "restrictbuildbuyinbuildings false" to build outside of your apartment unit. You might need to have testingcheats on, but I don't recall if it's actually necessary because I usually have it enabled anyway.
I assume you already tried changing the lot type to community and back after you swapped out all the apartment objects? If that doesn't work, I'd bet you still have a stray room marker or NPC door somewhere.
I will try setting it to a community lot and then switching it back. I've checked over and I don't have a hidden marker anywhere.
And, this may seem like a dumb question, but all the doors are from the base game, so do you set them as NPC? If so, how do you unset them.
In the eyes of the game though, they are the same thing. Your question doesn't make sense. House = Apartment, Apartment = House
I don't care about the eyes of the game. The simple fact of my problem is that I can't extend the apartment to the empty rooms in order to use them. So either way, whether I'm converting it back to a house, or just expanding the apartment by using the empty rooms, it's not working. My question makes perfect sense regarding the issue I'm having.