Having a table entry for the partnership means that at one point you had a client who was a partner, but you don't necessarily currently have a client who is currently a partner.

There is no easy way to identify who that other client is or was. If I wanted to take a stab at it, I would go into 2021 Lacerte, print the K-1 organizer page to PDF for all clients, squish them all into one PDF file, then use Find to search for the partnership name or EIN.