To send the PO Response to the initiator, the fulfiller sends the document (in Chem eStandards format) to the
pub.estd.chem:receive service. The
pub.estd.chem:receive service invokes the wm.ip.tn:recognize service, which recognizes the document and creates a BizDocEnvelope. The
pub.estd.chem:receive service sends the BizDocEnvelope to the Process Engine. The Process Engine searches for a running conversation (or process instance) where a
Wait for PO Response step is waiting for a PO Response with a matching ConversationID. When the Process Engine finds the correct conversation (or process), it sends the PO Response to rejoin the existing conversation.