How to change the relationship in CAS

Recently, i created two teen sims and mark them as sibling, but then  i found out that it's possible for them to become a couple, and now is the problem. How to change the relationship between them from brother/sister to roommates? I did apply cheats like cas.fulleditmode but somehow i also didn't manage to change their relationship from brother/sister to roommates. *They are both in love with each other, please give some advice, LOL.* 

I recommend trying the cas.fulleditmode again, you should be able to set them as roomates with it. If that won't work, then you can get the debug mod and you can edit the relationship there, to remove the brother/sister connection. SOmetimes this does the trick by itself, other times another try in cas.fulleditmode is required. If none of this works, then you can delete on of them and generate a copy from them that should be in your library.
I had the same problem, just reversed. For some reason something went wrong with the relationship of the goth family and Casandra and Alexander were no longer the children of Bella and Mortimer, but roomates.