If it were me, I'd  1)  report the sale on the Partnership return    2) report the sale on individual return with cost same as sale price  and under description enter "This sale is reported under (insert name of LLC here) EIN (insert LLC EIN here)          

not saying that's proper but that is what I would do           similar to how I would handle 1099MISC reported to taxpayer when it should be to SCorp or LLC