Purchase Requisition and blanket Release change management

Hi Friends,

We are receiving PO Recommendations from planning system (Not Oracle) and inserting into custom staging table

based on sourcing setup, we are moving data into PO_REQUISITIONS_INTERFACE_ALL table and spawning Requisition Import program and converting into Blanket releases.

If there are some changes in Planning system like quantity or need by date, How we can interface and update in Purchase Requisition and Blanket Release ?

After changes, Purchase request and Blanket Release should be approved automatically without manual action.

Please give some clue about this process

any inputs very much appreciated

Thanks

Laksh