CMP and "waiting" status

["Childs, Ed" <Ed.Childs@xxxxxxxxxxxxxxxxxx>]

The CMP document states that a CA can return a response message that
indicates 
a "waiting" status - necessary if a request cannot be immediately
authenticated and 
a certificate granted or the request rejected. However, it does not
explicitly state (or at 
least I cannot find it) how a requestor, who received "waiting" status,
should ultimately 
get the results of the authentication.

How does a requestor obtain the results and receive the certificate if
granted?