To get to the full edit mode in CAS with an existing sim (the adopted teen in this case)
Press CTRL+SHIFT+C all at the same time while in live mode.
Type TESTINGCHEATS ON
Press ENTER
Type CAS.FULLEDITMODE
Press ENTER
SHIFT+CLICK on the sim
Choose EDIT IN CAS
Make your desired changes to the sim then, click the check mark to exit CAS and return to the game.
Press CTRL+SHIFT+C again if the cheat console is not still open.
Type TESTINGCHEATS OFF
Press ENTER
Press ESC to close the cheat console.
