ProConnect Tax doesn't have the split MFJ function that exists in Lacerte.  I'd use the MFJ vs MFS comparison as the starting point then following Steps 1 to 6 outlined in this thread - but be forewarned that's a very manual process that may not be worth the effort, depending on the complexity of your return:

https://proconnect.intuit.com/community/proconnect-tax-discussions/discussion/re-how-to-create-the-c...