Place the duck on the second lowest rack of the oven, which should be pre-heated to 300 °F (149 °C). Roast, breast-side up, for one hour. After the first hour of roasting, pull the roasting tin from the oven and prick the duck's skin with a sharp knife to release the melted fat.  Pay particular attention to the areas around the legs, as these are particularly fatty. Flip the duck over so it's breast-side down, return it to the oven and roast for another hour. After the second hour, remove the duck from the oven, prick it all over to release the fat, then turn it breast-side up and return it to the oven for another hour.  After the third hour, prick the fat and turn the duck breast-side down and return to the oven for the final hour of roasting. The duck should be getting progressively browner and crispier as time goes on. After the fourth hour of roasting, remove the duck from the oven. Turn the oven temperature up to 400 °F (204 °C) and wait for it to pre-heat.  While you're waiting, spoon the duck fat from the bottom of the roasting tin. Be very careful doing this, as the fat is extremely hot and could cause a nasty burn. Once cooled, the duck fat will keep for several months in the fridge. It can be used to make delicious roast potatoes and veggies, or even to add flavor to a roast chicken! Once the oven reaches 400 °F (204 °C), place the duck back in the oven, breast-side up and roast for 10 more minutes. This will help the skin to get really crisp. After ten minutes, remove the duck from the oven. If you are using a glaze (like one of the ones described below), brush it liberally over the skin of the duck.  Then return the bird to the oven to cook for another 5 to 7 minutes at 400 °F (204 °C), until it is dark brown in color. Watch the duck carefully during this time, as you don't want it to burn! Instead of using a glaze, you can simply serve the roasted duck with a sauce on the side (recipes can be found below). If you go for this option, there's no need to return the duck to the oven for these final 5...

How would you rephrase that briefly using Vietnamese?
Quay vịt ở nhiệt độ 150°C trong 1 tiếng. Khứa da và lật vịt. Lặp lại quy trình như trên trong 2 tiếng tiếp theo. Vớt mỡ và hoàn thành quy trình quay thịt vịt. Phết sốt (không bắt buộc). Để thịt vịt nguội.