At a member organisation, staff linked two single members into a joint membership by hand. If one partner was unfinancial, the system blocked the link, so staff took that person’s single renewal, linked the pair, then refunded the difference.
We built a Link joint membership job in the Work Queue. A staff member starts it on one member and searches for the partner. The search shows each member’s official address and checks whether the two share it. Once the link is applied, both move to the joint fee and get one joint renewal, payable online or by phone, and they share a renewal date from then on. An unfinancial partner becomes active when the link is applied.
A person still decides whether two members should be linked and which record is the partner. The organisation chose how a joint renewal is paid when the two fall due at different times, because that sets what members pay and when.
In your own office, check whether staff take a payment only to refund part of it so a record fits a rule.