Fenna There's not really a "family" pack... do you mean the normal bunq Pack plan for 4 people? It can be used as a family, but also friends, acquaintances, or any other bunqer really. I have some wonderful people from this community in my pack that I don't even know the name of ;)
Anyway, as soon as you leave a bunq Pack, then you have to switch to any of the other plans. Normally in a Pack you get the equivalent of the Easy Money plan, with an option to upgrade to Easy Green (there's also an option to downgrade to Easy Bank, but I never understood why anyone would like to do so, as it doesn't become any cheaper).
So long story short: as long as you stay on Easy Money, then nothing will change at all. Except maybe your monthly invoice date. All your sub-accounts, all your cards, everything will just be as is right now.