A homeowner needs to fix a greywater drainage pit on a 1907 home that has zero slope, a blocked line, and a broken pipe connection at the pit wall, and is unsure how to properly connect new pipe given

A homeowner needs to fix a greywater drainage pit on a 1907 home that has zero slope, a blocked line, and a broken pipe connection at the pit wall, and is unsure how to properly connect new pipe given insufficient pipe stub length.