3 years?

Never mind - I misread the question. 

That didn't take long to find the need to amend.  You probably want to give the IRS a little time to process it before you try amending.  If you tried amended right after you got the original accepted, the IRS probably had the return out on some cooling racks allowing it to cool before they do anything with it.

Was there an extension?

If yes, you can file a superseding return by September 15, 2023.

If no, can you file an amended return? You can't if it's a BBA Partnership.

Is it 'safe' to assume this return was on extension?   If so, would this then be a superseding return?

And isn't there some wonkiness about amending partnership returns, depending on certain elections at the partnership level (or is that just if it's an audit adjustment?). 

As you can tell, I know just enough 'bout all this to be dangerous 🙂

Susan... jinx.  I was interrupted by a phone call.