The original bill was passed by a super majority in the Senate when the Democrats had sixty votes. The original bill was so badly drafted that they subsequently had to pass another bill to fix the first one and they did so by the reconciliation process because by that time they had lost their super majority in the Senate. According to Senate rules only spending and tax bills can be passed by the reconciliation process.
Then the Supreme Court found( contrary to its proponents in the administration and congress) that the act passed constitutional muster because it was a "tax", ignoring the fact that all tax bills must originate in the house of representatives, which the ACA did not.( Dingy Harry completely gutted an unrelated bill sent from the hose and inserted the ACA into the bill)
An argument goes that since the Supreme Court has declared that it is a tax it ought to be able to be rescinded by a simple majority in the Senate since under their rules a "Tax" bill can be passed by the reconciliation process.
In any case, the amending bill that was passed subsequent to the original, can be nullified by the simple reconciliation process in the Senate. By doing so it would so impair the original that it would collapse under its own weight. Think of the whole edifice as a three legged stool and you can cut off one of the legs then the whole thing falls over.
hose should be House although the original makes sense.