How to file a AMENDED 1120S when TurboTax says "You have no returns eligible for e-filing"?

[sales21]

It's clearly an amended return (the box is checked), but TurboTax says I'm not eligible to e-file because the file has already been transmitted (but that was the original one!)

[JotikaT2]

Make sure your original return was successfully e-filed and accepted first.  

Once you confirm the return was successfully filed and accepted, then follow the steps here to start your amended return.  There may be a step listed here that needs to be followed to ensure the amendment is created correctly.