Creating a drop ship purchase order from intercompany sales order is currently not supported as it may cause inventory in transit discrepancies.
In the current Intercompany Drop Ship feature, the following workflow is supported:
1. Subsidiary A creates a Sales Order to an external customer with drop ship item with an intercompany vendor as the preferred vendor.
2. NetSuite generates an intercompany drop ship Purchase Order for Subsidiary A based on the Sales Order in step 1.
3. An intercompany Sales Order for Subsidiary B is generated from the purchase order in step 2 at the Manage Intercompany Sales Order page.
4. Subsidiary B ships the order to the external customer for Subsidiary A.
The following workflow is currently not supported:
1. Subsidiary A creates an intercompany Purchase Order.
2. An intercompany Sales Order for Subsidiary B with drop ship item for an external preferred vendor is generated from the purchase order in step 2 at the Manage Intercompany Sales Order page.
3. System generates a drop ship Purchase Order based on step 2 for an external vendor.
4. External vendor ships the items to Subsidiary A.
For more information about the Intercompany Drop Ship feature, read on the SuiteAnswers article about Intercompany Inventory Drop Ship (Answer Id: 24135).