Add the following statement:
* Moderator= All,email@example.com
This will cause all posting approval requests to be sent to all moderators.
Any moderator can approve the request. If a moderator attempts to approve a request which has already been approved, LISTSERV will issue an error message to the effect that there is nothing pending with that code. You can use the web interface to get a list of all pending messages, and explicitly reject or approve individual messages.