can IDOC PORDCR1 be used to change PO

Hi Experts

PORDCR1 IDoc is for BAPI ALE messaging and will execute the BAPI_PO_CREATE BAPI and used to create PO.

can I use IDOC PORDCR1

only to create Purchase orders or can I change POs as well?

Any clue what I have to maintain when I want to create change orders?

Thanks.