Since you are asking other users you need to ask a full and complete query.

What flavor of K-1?

What is the description of line 19?

Have you taken the time to read the instructions for the taxpayer that would normally have come for the K-1?

I'm preparing a partnership return and I need to enter the passthrough K1 information because it (the partnership) received a K1 from another partnership. Line 19 is the distribution line. There are tabs in the entry screen that divvy up the K1 lines. There is a tab that says Lines 12-19, but there is no space for Line 19 input on that tab.

Your partnership received a distribution from another partnership; the K-1 you provide your partners should only reflect the distributions they received from you.

On your trial balance, those distributions from the other partnership should match the distributions you booked as a reduction of (credit to) "Investment in Other Partnership."

Okay, I understand mostly. But where do I enter the distributions the partnership received? In Lacerte, I put that in Box 19 in the passthrough K1 screen. There's no such screen in Proconnect. So I don't know where to enter it.

Why do you need to enter it anywhere? When you entered it in Lacerte, how did that affect the tax return?

I guess that's one of my questions too. Do I even need to enter it? It's looking like I don't need to. And I think in Lacerte it ended up on the 1065 on Sch K, Line 19. 

No it didn't. As Phoebe said, only distributions from the partnership whose return you are preparing to its partners go on Line 19.