The operation can add, update, and remove items from an existing inbound shipment. If you include the Inbound Shipment Items request parameter, the behaviour is as follows: 

Include an item that doesn’t exist in the inbound shipment, as identified by the Seller SKU, adds a new item to the inbound shipment.

Include an item that already exists in the shipment, as identified by the Seller SKU, replaces the existing item. Note that if the new item that replaces the old item has Quantity Shipped set to zero, this indicates that the item is removed from the inbound shipment.

Cancel Inbound Shipment

If an inbound shipment is not shipped then the user can cancel inbound shipment from Odoo to Amazon and inbound shipment state will be cancelled in Odoo. After cancelling inbound shipment user cannot edit or reopen it again.

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