When you send a PO change acknowledgement to the retailer and wait for the Change response the order awaits without processing ahead to accept the changes. 

There is a setting to time out the waiting period, so the system waits until that particular time from the moment where the PO change acknowledgment is sent, and it automatically accepts the change  and process the order ahead even if the response hasn't come.

If you go to the retailer settings you will find the setting under PO Change Timeout;

 As per the above settings the system waits for 4 hours, and if the change response hasn't received within the 4 hours it automatically accepts the changes and process the order ahead.

Please contact support@theorderexchange.com.au if you have more issues.