Is there a way to reset the "amend return" section back to the way it was filed? I made some changes, but things went off the rails. I want to start fresh.

Are you using the Online version or the Desktop program?  

You can delete the amended return this way.  Do the steps slowly and carefully.  After you delete it then you need to manually take out the changes you made to put your return back to the original return.  Or in the Desktop program you can start over in a copy of the original file if you made a copy to amend in.  

How to delete an Amended return in the Online version

https://ttlc.intuit.com/community/amending/help/how-do-i-cancel-or-undo-an-amended-return-in-turbotax-online/00/26315

In the Desktop program all you have to do is go to Forms mode and delete the 1040X.  Then take the changes out.

Cancel or undo Amended return in the Desktop program

https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/cancel-undo-amended-return-turbotax-cd-download/L7glUWakU_US_en_US

Sorry the link for the Online version changed.  I haven’t found a current one yet.   

The AMEND command should warn you that you are about to lose your original filing if you proceed without copying to a safe place or making  a paper copy, or both.

For some reason, Intuit does not think this is important information.

@andy102