Hi,
As of my knowledge, once the PO is saved, you cant put it on hold.
I would suggest the following options:
1. Configure release strategy for PO and maintain the release indicator as 6 (Changeable, new rel. if new strat. or value change/outputted)
2. Check the output type and go to NACE transaction. Now, go to condition record and maintain the condition type for the message type with "date and time" as 3 (Send with application own transaction)
If the PO release is triggered again, the PO wont be outputted unless the PO is released. If you give the date and time for the message type as 3, system wont output the message automatically, you have to do it ME9F transaction.
Regards,
AKPT