Where did I say argue?  But I believe the expression is "one and the same."  You can use a 1040-X for a superseding return,  and you don't have to write anything across the top of it.  In this situation, though, it's probably easier for everyone to prepare two oriiginal returns and do IRS the courtesy of letting them know that they already received a joint return.  Remember they work for you, you don't work for them (although they have succeeded in turning most of us into data-entry clerks).