No, data conversion only works with current year tax returns.  You can convert a 2019 return from TurboTax into a PTO return for 2020 only but not 2019.

If all you want to do is to produce a 2-year comparison based strictly on what is shown on your client's return as prepared, you can check to make sure the prior year amounts in Other > Prior Year Summary are correct and edit as necessary.

Thank you!