Gift recipient return — store credit to recipient, not card to purchaser

Hi there, I hope this isn't too much trouble. My aunt bought my daughter a dress from your store for her birthday — it's a really beautiful dress and we both love it, but unfortunately it's the wrong size. My daughter is kind of between sizes at the moment and the one that was sent is just too small. There was a gift receipt in the package but I can't see an order number on it anywhere. I'm not sure if I'm even able to return it since I wasn't the one who placed the order? I really don't want my aunt to find out because she'd feel terrible and she put so much thought into choosing it. If there is a way to sort this out without her knowing that would be amazing. Thanks so much for your help, Chloe