If the person has the design in their dream address and allows you to take patterns with, you can download it from there.
Otherwise, it's sort of roundabout, but you could get a friend to edit the QR code to contain their identity (you'll need a tool to do this, I think if you look up ACNL QR code editor, you'll probably get something). Then have them display it in their Able Sisters', and get it from there. Of course, this only makes sense if the friend isn't someone you can meet up with in real life, or if you have a digital copy, since otherwise it would probably be quicker to just borrow their 3DS and scan it from there (unless their 3DS time is very different from your town time, of course).