Sai who? Sophisticated and versatile, the Sai Dress by Reformation is equipped for any scenario with its sleeveless maxi silhouette and turtleneck neckline. Sai who? Sophisticated and versatile, the Sai Dress by Reformation is equipped for any scenario with its sleeveless maxi silhouette and turtleneck neckline. Founded in 2009, Reformation is a revolutionary lifestyle brand combining stylish, vintage-inspired designs with sustainable practices. With each limited-edition collection, the LA-based brand empowers individuals who want to look beautiful and live sustainably.