In 2019 Screen 3, last item of Miscellaneous is a check bot for Converted Client ... If you have reviewed the 2019 for accuracy, including items like carryover, depreciation, state then remove the check mark and the 2020 proforma will have what you want. 

Unfortunately that is not well advertised to those that do conversions. If you are not too far into input on the 2020, then remove the check mark and do the proforma again.