Give-up trades work when one party is unable to place the trade, so they entrust the trade to a third party. If John wants to buy ABC stock but is unable to place the trade with Andy, who owns the stock, John may have Mary make the trade for him, delivering the stock from Andy to John after John has paid. There can be four total parties if in this example Andy is also unable to make the trade personally. Nowadays, this is done electronically.