One way, assuming it is LISTSERV and not the mailer/SMTP hiccuping, is to go into the list's
Moderation web page and follow the instructions for purging the Moderation Request.

On 2/14/2011 11:23, Frank Bures wrote:
> Hi,
>
> some time ago I got a request to delete a subscriber from a list.  I did
> so, but before I received the confirmation request from the listserv, the
> requester retracted his request for deletion.  So I just ignored the
> confirmation request hoping it will go away in 48 hours as it usually does
> in such cases.
> However, this time the request has not been deleted and the confirmation
> request keeps popping up in my mailbox now and then.
>
> How can I get rid of it for good?
>
> Thanks
> Frank
>
>