Here is why we have to repeal HCR: If we settle for simply "modifying" it, the Democrats will hold us up for blame for everything that gets screwed up in the "health care system" (I hate that term) going forward from here. They'll claim that "the original bill handled that problem, but the GOP took out that mechanism so now it's a disaster." The media, of course, will back them up on this.
That's why it's got to be "end it, don't mend it."