If the item you'd like in exchange is out of stock, your best option is to make a return for store credit instead. Store credit is issued in the form of a virtual gift card (or physical gift card if brought into the store), can be used online or in-store, and never expires. From there, you can sign up for restock notification to be notified when the item you want has been restocked. If it's an item that won't be restocked, the store credit can be used toward any other item!