It is not possible to stop payment on a postal money order. However, some money orders can be replaced if they are lost, stolen or damaged.
It is possible to stop payment on a check because there is no money deducted from the check writer's account until the check is cashed. However, postal money orders must be paid in full before they are issued. The USPS does not permit customers to purchase money orders with checks or credit cards, so the customer cannot issue a stop payment or chargeback for the cost of the money order. Though the USPS provides replacements for uncashed, lost, stolen or damaged money orders, there is no procedure to refund a money order if the customer changes his mind.