Get your taxes done using TurboTax

There are two key steps:

• Figuring out the correct cost basis for your AGQ.  Its not the $6000 you originally spent.  Its going to be $6000 plus whatever adjustments to basis are reported on your K-1.
• Entering the actual sale.  In the K-1 interview, when it asks you about the sale, the recommended way is to enter 0 for proceeds and 0 for cost.  If you do this, the K-1 interview won't duplicate your 1099-B.  If you instead enter values here, the K-1 will create a new 1099-B (code C or F) duplicating the one the broker sent you.

I always keep the K-1 from creating a new 1099-B.  It seems simpler to me.  So if you do that, you'll just need to adjust the cost basis on the 1099-B to reflect the correct number.