For 2019, my client's S-Corp had a $44k loss. How can I carryback this loss against the company's $18k income of 2018? I filed both 2019 and 2018 1120S returns, before realizing I could use the carryback. Do I need to file amendments for both years, or just for 2018? And, exactly how do I go about implementing the carryback within ProConnect? TIA.