put https://marketplace.walmartapis.com/v3/ca/fulfillment/shipment-quantities
Seller can modify the shipment quantity before the Shipment arrives at the WFS FCs. Seller cannot modify the shipment quantity when Shipment Status = Receiving in Progress, Closed, and Cancelled.
Seller will need to provide new quantities for each SKU to update. Seller will only be able to add up to 6 units per SKU but can reduce to 0 units to remove any SKU from a shipment. Seller cannot change all SKUs’ quantity to 0 – they must cancel the entire Inbound Order.