If your goal is to revise shipping details for an existing listing, you should be aware that the approach for revising the listing differs from the typical approach for revising a listing.

To avoid loss of shipping details, do not omit any tag when revising shipping details, even if its value does not change. Omitting shipping fields while revising an item will remove that detail from the listing.

For example, if you specify ShippingDetails when you revise or relist an item but you omit its child field InternationalShippingServiceOption, eBay will drop any international shipping services from the listing.

Note: One exception to this behavior is the boolean ShippingDetails.GlobalShipping field. If you omit this field when revising or relisting an item listing, its value will be unchanged. A listing that offers Global Shipping will continue to offer Global Shipping unless you explicitly include the GlobalShipping field with a value of false.

To find out the shipping fields present in the current listing, call GetItem and look through the Item.ShippingDetails fields in the response.

For multi-quantity Fixed Price listings, a seller can revise all shipping details of the listing (except for sales tax and for shipping type of Freight) for all unsold items. This applies to both domestic and international shipping. Checkout is not affected for those who bought items prior to the seller's shipping changes--the shipping details that were in effect at the time of purchase are used for that buyer at the time of checkout.

For additional information, refer to: