Customers can replace an item with a different product

The Replace a product tool lets a customer swap an item on their order for any product you offer, right from the thank-you or order status page. A pricier replacement is paid through Shopify's own payment link. A cheaper one shows the refund before the customer confirms, and the difference is refunded once you approve it, or automatically if you chose automatic refunds. You can still set a price limit in the tool's settings, and choose which collections can be swapped in.