I think it will try to put you through New York maybe? I used NW miles for a ticket on Delta last summer through ATL from IAD. The ATL-SCL flight was cancelled because of mechanical issues, so I got a free night in the Red Roof Inn and some free meals while spending an extra TWENTY FOUR hours in Atlanta. The way they handled the rebooking was rather disastrous....there was a mob of angry Chilean people about to jump the counter in E terminal. We were originally told the flight would leave early in the morning, but they ended up just putting us all on the next days flight since the load was about 50%. Then, that flight was on some ratty old 767 they pulled out of who knows where. My reading light switch and my seat partners were switched somehow, and entire bank of lights wasn't working. There were also problems with the toilets, but they got it fixed before takeoff. After complaining before leaving in the CRC, they changed my fare class for the ATL-SCL flight to Y, and I later wrote a complaint letter, which yielded 2500 miles, giving me a total of 10k miles on an award ticket!

All I can say is Im glad I had purchased the 60 day Worldclubs membership for this summer, I spent the entire day in the CO and DL lounges in Atlanta...free booze and snacks. The CRC in Santiago is also pretty nice.

The return flight was on a much better 767, tho still no IFE at the seat. Regardless, the length of the flight+the fact that there is no time change makes it PERFECT for taking a sleeping pill and getting a good night's rest.

Flying into Santiago in the morning, I had a window seat on the left side, giving me a beautiful panorama of the Andes.