Hi @chenwm 

Once Inventory is posted you need to follow the below steps to process inventory reverse but we cannot do anything with an updated shipment.

We can reverse the Inventory by placing return orders in Acumatica. The below steps may help you.

1. Create a Return type of order ex: (RC type - RMA )
2. Create Receipt for this order (From Actions) 
3. It will create shipment type as a “Receipt” and then click on Update IN (It will reverse the Inventory)
4. Prepare an invoice and then will create a “Credit Memo” document. 
5. If Aleady payment is collected for the actual order, we need to create a “Customer Refund” in the Payments and Applications screen for the actual payment.
6. Finally, apply the below documents to the Actual Payment and release. Payment and Invoice will be closed.
   1. Credit Memo
   2. Actual order Invoice

Thanks

@manikantad18 hi thanks for the workaround, let me try it first.

Why do we click Update IN?  The inventory transaction will occur once the credit memo document is released.  Seems like an extra step.