Charlotte Howard wrote:

Hello Brian, how exactly should he do that?

In the To field of a new message, enter the first character of the DL name.
When it appears, hopefully it will be in a pop-up list and you'll be able to
use the down-arrow key to highlight it and then press Delete. This will
remove it from the autocompletion cache. He can then rechoose it from the
Contacts folder in which it is defined, pressing CTRL-K to re-resolve it.
--
Brian Tillman