If you started to use Blanket PO and need to change the Control Line Increment you will need to remove all existing Blanket POs.
Delete, Void, or Cancel all open Blanket Purchase Orders. This is required because after you change the Control Line Increment, the Blanket PO module will no longer recognize Blanket POs created with the previous numbering sequence. If you already have completed receipts against Blanket POs, once those POs are closed and the Control Line Increments is changed, you will not be able to view those POs in the BPO Inquiry window.
Use SQL Management Studio to run the following update. This query will re-enable the Control Line Increment field.
Open Blanket PO Setup and enter the new Control Line Increment.
Control Line Increment will lock again the first time you use the Blanket PO Entry window.