Rotate with Move Tool

Select one face of the sheet metal wall and rotate it with the Move handle. If you select the inside of a face to rotate around the inside bend center, or select the outside face to rotate around its outer mold line

A default junction to rotate around is chosen based on which junction causes the smaller portion of the part to rotate. To rotate around the other junction, drag the Move handle anchor (the center ball) to an edge on the other junction.