Then , the audience must vote for one of the bottom two couples via text messages .
In the Duel , the couples must perform the same dance again and the judges will determine which couples will advance to the next round until only two couples remain .
The audience must vote for one of the bottom two couples via text messages .
In the Duel , the couples must perform the same dance again and the judges will determine which couples will advance to the next round until only two couples remain .