Some Retailers such as Coles don't want to receive any Acknowledgements until all changes have been confirmed - so POA needs to be turned off until the Order has been confirmed.

Standard setup for this is to set the Order Send Change Prior to Despatch as per image below;

If you need to also send an ACK if there are no changes then Must send change needs to be ticked as per image below

Lastly Acknowledgement Type needs to be empty and PO change type needs to be setup as per image below;