On the Process Editor canvas, select an Invoke activity.
In the Properties view, click
Dialog (...)
.
Select a correlation set from the list.
Select one of the following from the Initiate list:
Yes
to start correlation in this activity.
Join
to start correlation in this activity, if it has not started yet. This is useful for multi-start activities, such as several receives inside a flow or scope. Select
Join
for each receive.
No
if this activity does not initiate correlation.
Se Pattern to one of the following:
Request
to correlate the input message.
Response
to correlate the output message
Request-Response
to correlate both messages. This is useful when both the input and the output message are part of the same conversation, and both contain a property alias for the same property.

If needed, click
Add
to add another correlation set for this activity.

<invoke partnerLink="Seller" operation="SyncPurchase"
        inputVariable="sendPO"
        outputVariable="getResponse">
  <correlations>
    <correlation initiate="yes" set="PurchaseOrder" 
                 pattern="request">
    <correlation initiate="yes" set="Invoice"
                 pattern="response">
  </correlations>
</invoke>