You will need: one pair of pants your daughter has outgrown and one shirt that your daughter has outgrown.
Cut the pant legs off just above the knee, this allows for a seam allowance. Either pick the inner leg seams open or cut them off. I cut. Smooth out the pants and you will now have a pant triangle that is open on the inside, kind of like a letter “A”.
Cut each half of the shirts apart and slide a piece into the “A” and measure to fit. Sew the shirt to the legs.As you can see the skirt is rather pointy in the front so cut and hem that.