If you followed the amend process in TurboTax online, then you just click cancel amend and nothing will be saved.
If you amended with the desktop version, then the amend is a separate file and can be deleted without affecting the original return.
If you attempted to amend in your original file and not with the amend process, then you cannot back out of the changes and will need to manually change the return back to its original state.
Always make sure you are following the amend steps property.
How to Amend
