In all Sims games, the player has the option to change the house their sims live in.
In order to move, you must click on your phone and click "move". Then select all the sims you want to move, and click the arrow and then check the box for whichever sims you want to play with. Then click either "house" or "lot" and take your pick. if you are having just a few sims move out and you're playing with the family that lives there, just choose the "kick out" option which gives them a random house for free!