How to alter a dress with ruched sides?

I bought a bodycon dress that is too loose at the waist, I’d like to take it in at the waist to make it fit my waist. How would I alter it, since there is ruching at the sides?
For reference, here is the dress:
https://www2.hm.com/en_gb/productpage.0918947003.html
It would cost more than what I bought it to alter it professionally.
Replies
I have altered dresses with this type of design. You just need to maintain the slight gathering along the seam lines. If you can put the dress on inside out and lift the lining to allow access, you can pin the amount you wish to take in, and use multiple pins to keep the ruching design in place. Good luck