Unfortunately not, tickets are non-refundable, but they do make great gifts. You can contact us to change the date on the tickets to use them at a different time, as well.
However, if you purchase a new order with the correct amount of tickets you intended to have in the first place, you can contact experience@LEGOLAND.com team who will issue a refund on the first order with too many accidental tickets. With this, please make sure you include BOTH order numbers and the situation so they're aware you did purchase a second order and get a guarantee refund for your first order.