Choose a well know solo or melody to sing in unison with your choir. I like to use “Somewhere Over the Rainbow”.
Once you are confident they know it, ask your singers to move around the room singing it to as many different different people as they can, as if they are a soloist. You will have parrallel solos. They are all singing the solo at the same time to each other and alongside each other.
Once they have sung a line or two they can swap partners, but let this happen naturally.
Encourage them to sing directly facing another person and to be expressive and dramatic.
What do you discover happens? How do you singers feel afterwards? Did you see any transformations?