Lilly Pulitzer NWOT Lace-back Cocktail Dress - Size 2

This is a stunning dress from Lilly Pulitzer. It is a burgundy/plum color with see through black lace panels on the back and arms. The lace is a continuation of the inner lining so it acts as a slip. The material is a soft spandex and knit mix that typically offers some forgiveness even though it is a tight woven and structured textile. The dress is new without tags and a size 2.. I purchased this for my baby sister and she just sent it back to me after taking off tags and deciding it was too big. She is a 2 and if she thought it was too big, I assume it fits like a 4.