Previously, the SKU swap ("Change Product") button was only visible to customers within their SMI if the product they were subscribing to was both in stock and SKU swap eligible. This isn't helpful if their product is out of stock and the customer would still like to receive their subscription. We've updated the SMI so that now the SKU swap button will display whether the product they are subscribing to is in or out of stock. This way customers can swap to another flavor/variant when their subscribed to product goes out of stock and keep their subscription going!