How do I remove walls?

Open the store while in the house you want to remove the wall. Then tap Rooms. Tap in the middle of the room you want to remove and then tap in the red squiggly with the price tag. This will remove the entire room even the furnisher and floors, windows, etc. I don't know if it will but it in your inventory so you may want to put w.e. Items you want to save in another room or put it in your inventory. The price will reduce the worth of your town also. To avoid this, you may want to add a little room first and then resize it by moving the wall that was once exterior. Then you can add a door or an open doorway.

Thanks so muh for the answer.

I am trying to figure out how to remove one wall, not a whole room. I want to make a room that has a different shape other than a square or rectangle. Can this be done?