The ProxyRequest function proxies the current SIP request to the supplied URI.
void ProxyRequest( string uri );
If the request has a strict route (the "Route" header is present and populated), you must only pass the empty string as a parameter. Alternate destinations are not allowed in this case.
This function will raise a critical MSPL error if the current message is not a SIP request (see the description of the sipRequest built-in variable in MSPL Built-in Variables).
Calling ProxyRequest(sipRequestUri) to change request-uri in effect marks the request as routed without providing a request target. Applications that do not have routing information for a request should not modify the request-uri. In general, we recommend that non-routing applications never change the request-uri.