3.3 Formulating a Reply Message This section specifies Addressing-specific rules for creating a reply or fault message using the appropriate message addressing properties. Select the appropriate EPR: If the reply is a normal message, select the EPR from the incoming message's [reply endpoint] message addressing property. If none is present, the processor MUST fault. Otherwise, if the reply is a fault message and the incoming message's [fault endpoint] message addressing property is not empty, select the EPR from that property. If the [fault endpoint] property is empty, select the EPR from the incoming message's [reply endpoint] message addressing property. Otherwise, if the [reply endpoint] property is empty, the behavior of the recipient of the incoming message is unconstrained by this specification. In either case, if the incoming message lacks a [message id] property, the processor MUST fault. Populate the reply message's message addressing properties: [destination]: this property takes the value of the selected EPR's [address] property [relationship]: a new pair of IRIs is added to this value as follows; the relationship type is the predefined reply URI "http://www.w3.org/@@@@/@@/addressing/reply" and the related message's identifier is the [message id] property value from the message being replied to; other relationships MAY be expressed in this property [reference parameters]: this property takes the value of the selected EPR's [reference parameters] property The following example illustrates a request message containing message addressing properties serialized as header blocks in a SOAP 1.2 message: Example 3-1. Example request message. http://example.com/someuniquestring http://example.com/business/client1 mailto:fabrikam@example.com http://example.com/fabrikam/mail/Delete 42 This message would have the following property values: [destination]: "mailto:fabrikam@example.com" [reply endpoint]: The endpoint with [address] "http://example.com/business/client1" [action]: "http://example.com/fabrikam/mail/Delete" [message id]: "http://example.com/someuniquestring" The following example illustrates a reply to the above message: Example 3-2. Example response message. http://example.com/someotheruniquestring http://example.com/someuniquestring http://example.com/business/client1 http://example.com/fabrikam/mail/DeleteAck This message would have the following property values: [destination]: "http://example.com/business/client1" [action]: "http://example.com/fabrikam/mail/DeleteAck" [message id]: "http://example.com/someotheruniquestring" [relationship]: ("http://www.w3.org/@@@@/@@/addressing/reply", "http://example.com/someuniquestring")