I printed my return to check it over, amended it, printed it and now I need to go back to the original one. NOTHING has been mailed. Can I efile the original return?

If you made changes to your return that you now wish to undo, you'll need to manually reverse the changes you made before e-filing.  

Use the instructions below to re-open your return after printing it.  This should allow you to make changes before you proceed then to the FILE section and choose to e-file your return.

https://ttlc.intuit.com/replies/7306547