Maybe @IntuitAustin could get a article posted on the steps for this process. In the meantime @itonewbie posted a "How To" in this question https://proconnect.intuit.com/community/proconnect-tax-discussions/discussion/how-to-create-the-curr...

 PTO does not have a function to split MFJ returns automatically.

1. Make a copy of the original return so that the filing copy will remain intact;
2. In the newly created return, you need to make sure your prior year return had every income, expense, and credit coded corrected for TSJ;
3. Check the MFJ comparison to make sure the allocation is in order;
4. Make one more copy of this return;
5. In the first copy you made in #2, remove all the entries coded S and manually split the amounts coded J;
6. In the second copy you made in #4, remove all the entries coded T, manually split the amounts coded J, and, finally, recode S as T;
7. Proforma both of these returns to create their 2019 returns; and
8. In each of the 2019 returns, you will need to manually allocate the 2018 taxes from the original MFJ return for F.2210 and YOY comparison.