LLCs are regulated by state law, so you have to check the laws of your state. The only federal issue I can tell you about is that when an LLC changes ownership (adds or removes a partner) it needs a new EIN.
I have a 2 member LLC and they have transferred their ownership to two other individuals.
May have this wrong because of the language but if one of the 2 members transferred their ownership to two others then the LLC probably doesn't need a new EIN.
it would seem that for federal purposes a partnership return need to be filed eaxh year.
under current law there is no termination of the partnership for federal purposes
see this link we're post TCJA
the transfer if partnership interest may result in tax consequences for both the terminating members and new members
section 751 may affect the terminating partners