Once you have selected to amend and have made the amended entries, you cannot go back to the original. You will have to delete the 1040X as illustrated in this thread and then revert back to the original entries. For example, if you added a w-2 for the amend, you would delete that. If you changed a number on a tax document such as a 1099, you would manually change it back to the original.
Tax programs used by paid preparers, instruct the preparer to make a copy of the tax return before amending. That way the original is there.
That being said, you can always download the original 1040 you prepared to see how it appears.
