Switch bills of lading: which fields may change, and which may not
A switch bill is a second set of original bills of lading, issued by the carrier to replace the first, usually at a different port. It has a bad reputation that it mostly does not deserve. The legitimate use is ordinary triangular trade. The illegitimate use is easy to describe exactly.
Why anyone does this
A trader in Singapore buys from a factory in Vietnam and sells to a buyer in Rotterdam. The first bill names the Vietnamese factory as shipper. If the trader hands that to the Rotterdam buyer, the buyer now knows the supplier and can go direct next time.
So the trader surrenders the first set and asks the carrier to issue a second set naming the trader as shipper. Same cargo, same container, same voyage. The buyer gets a document that works and does not name the factory.
What may change
Shipper. This is the reason for the switch.
Consignee and notify party. The onward sale is to a different party.
Port of loading, where a genuine transhipment means the second leg starts somewhere else.
Goods description, within limits. Usually this means removing a supplier's part numbers or branding. It does not mean changing what the cargo is.
Freight terms, because the trader's arrangement with the buyer is different from the factory's arrangement with the trader.
What may not
Container number and seal number. These identify a physical container that was sealed once.
Gross weight. It was weighed. Under SOLAS it was also certified.
Vessel and voyage. The ship sailed when it sailed.
Quantity and package count. What went in is what is in there.
Changing any of these is not a switch. It is a document describing a shipment that did not happen. A carrier asked to issue one should refuse, and generally will.
The rule the carrier enforces
The first set comes back before the second goes out. All originals must be surrendered before anything new is issued.
This matters more than it sounds. If both sets are in circulation, two different people hold documents of title to one container. One of them collects the cargo. The other has a claim. The carrier, which released against a valid original, is caught in the middle. That is why carriers require a letter of indemnity for a switch even when the request is completely proper. It is also why some refuse to do a switch on cargo under a letter of credit.
Before you ask for one
Check the letter of credit, if there is one. Many credits require the bill to show a specific port of loading or shipper. A switch set that no longer matches makes the presentation discrepant.
Check the origin documents too. A certificate of origin naming the factory, presented with a switch bill naming the trader, raises exactly the question the switch was meant to avoid.
And ask early. A switch is arranged with the carrier at the port where the first set is surrendered. Arranging it while the vessel is already discharging is not a quick conversation.