I have a scenario in which the Material type is ERSA, the MRP type is VB & the reorder point is 260. If i run MRP a PR gets generated for 260. I convert this PR to PO. I go back to the PO change the Delivery date and run the MRP again. Once again a PR gets generated. How to avoid this. Some config needs to be done
check whether you have maintained the rescheduling horizon in plant parameters
oppq and the try to run MRP.
Try to increase this horizon and check whether your PO falls within this horizon.
Now if you run MRP no PR will be created.