Reset:
- open cheat console (shift, ctrl, c)
- type in: resetSim *
- hit enter
Try again, if that doesn't work, try this:
- go to edit town (can be found in the popup menu along with save / quit / options )
- click on household and move them out (split household works quite nicely)
- put them back in and take them as your active household
I would also save the family to library before evicting them
