When you view the "KJ Rotation", kJams lists, next to each singer, the song they will sing in that rotation.
But the song is actually a popup menu that would let you pick which song for the singer to sing, it is the same list that is in that singer's "Tonight" list.
If the singer gets to the stage, and decides at the last minute they actually don't want to sing the song that's up for them, you can easily pick whatever song they want from their list, right in the "KJ Rotation". This is a time-saving feature that replaces the sequence: stop rotation, go to singers list, find singer, select singer's tonight list, drag-reorder the list so the song the singer wants is at the top, go back to the rotation playlist, start the rotation again. Whew! Now all that is one click!!