Reason for why can't change SO and PO

We would like to refresh you mind of certain scenarios in SAP where modifications to price, quantity, or delivery date in Sales Orders (SO) or Purchase Orders (PO) may not be possible. Below are the key restrictions:

After Goods Receipt (GR) or Invoice Receipt (IR) for PO

Once a Goods Receipt (GR) or Invoice Receipt (IR) is posted for a PO, the following fields cannot be modified:
- Quantity
- Price (if IR is posted)
- Delivery date (if GR is posted)

After Delivery or Billing for SO

For Sales Orders, if a delivery document or billing document has been created:
- Quantity cannot be reduced (increases may be possible under certain conditions).
- Price changes may require credit/debit notes if billing is completed.
- Delivery date cannot be updated if the shipment is already processed.

System Status Restrictions

If the SO/PO is marked as "Closed," "Completed," or "Blocked", no changes are allowed.
For POs with approval workflows, modifications may require re-approval.

Next Steps

If you encounter a situation where changes are needed but restricted, please:

For POs: Reversing the existing one, creating a new PO or canceling.
For SOs: Billing corrections or delivery rescheduling, Reversing the existing one.

Thank you for your attention. Let us know if you have any questions.