You can use the steps here How do I cancel or undo an amended return in TurboTax Online? to undo that accidental amendment if you are in TurboTax Online. Once you undo it, you should then be able to file the original return. The government doesn't receive the amendment since you have to print and mail amended returns for them to be processed.
And if you are not using TurboTax Online but using the CD/download version, you can go here for steps How do I cancel or undo an amended return in the TurboTax CD/Download software? to undo that amendment.
Let me know if you have anymore questions!