I shorten my dress to turn it into a top. I sewed a piece of black cloth cut-off from a unwanted t-shirt to the top. It made to looked like there's a shirt/tube worn with the low-cut top.
I used the remain cloth from the dress to made a dress from my daughter. I hand sew the dress with an elastic band to the top to make it expandable and also used the same cloth to made the sleeves.