Just in case 
Since it’s a bit hard to find/unintuitive
First go to the map by pressing ‘M’
In the top left corner, click on ‘All Families’
chose ‘Move Zois Between Families’
then chose the source family (you want Zoi(s) to move out from) and the family you want to move your Zoi(s) to
or, if you want to move Zoi(s) to a new household: chose ‘Create Temporary Family’ and the source family (you want Zoi(s) to move out from)
(imo this title is a bit misleading. When you move your Zois there, the Family will stay for good)
this is how it looks like, with the two arrows you can move the Zois between housholds (by clicking on the Zoi and then on the arrow) and with ‘Send Assets’ you can also move funds between the housholds.
‘Pro’ Tip (^^’)
If you want to move your new created household to a new lot, you might want to cheat enough money 
beforehand 
(I forget this each and every time omg and then I have to do this all over again ö.ö’)
‘Pro’ Tip 2
Make sure the Zoi you want to move is not the active Zoi, since you can’t move the active Zoi (the one greyed out in the pic above with the lock symbol on his face
(I really wish they’d fix/change that since I also forget this each and every time omg and then I have to do this all over again ö.ö’)
Don’t hesitate to ask/yell if sth is unclear/doesn’t work/I made a mistake