Is it permissible to fast the six days of Shawwal before making up a day from Ramadan?

If you have one day of make-up fasting (qada') from Ramadan remaining, and you wish to fast the six days of Shawwal, then you should first fast the day you missed. This is because the reward for fasting the six days of Shawwal is for those who have completed fasting all of Ramadan, in accordance with the hadith: "Whoever fasts Ramadan then follows it with six days from Shawwal, it is as if he has fasted the entire year."