Switch bills may be requested for a few different reasons, when there has been a change in the original trading conditions, goods have been resold (probably high-seas sale) and the discharge port has now changed to another port, the seller (who could be an intending agent) does not wish the name of the actual exporter to be known to the consignee in case the consignee strikes a deal with the exporter directly, the seller does not want to know the buyer to know the actual country of origin of the cargo so he requests that the port of loading be shown as some port other than the one the cargo was loaded from.