How switch primary and secondary taxpayer on an MFJ return? One spouse has already filed their individual return and indicated that was MFJ.

[tfiggatt1]

Facts: For TY2020, one spouse filed just their own information in March, 2021, but indicated their return was MFJ.
Other spouse has not filed TY2020, put that return (MFS) on extension to 10/15/21.

Is it best to either:
a) File an amended return with the first-to-file individual as the Taxpayer?
b) Switch the on-extension spouse to the Taxpayer position and amend?
Suggestions appreciated.

[IRonMaN]

I would vote for "a".  Hopefully the voting goes smoother than it did last November.

[BobKamman]

Are both spouses now willing to sign a joint return?