It depends a bit.
If we have not ordered your product from our supplier, we can exchange your order as long as it has not been sent from us.
If you have paid by card or Swish, we cannot increase the amount so the new product must cost the same amount or less. (If it costs less, you will receive a refund)
If you have chosen invoice, we can usually increase the amount by 20% of the order value, so you can then exchange for a slightly more expensive product if you want.
If we have ordered a product from our supplier for your order, we can exchange it without charge if we can cancel it with our supplier.
Otherwise, you can exchange but with a fee, which is usually 25% of the product's price.