I have both of my cell phones linked to Google Voice, so the phone company
voice mail almost never gets used.
This weekend I loaned her one phone because she had left her own in the
office, and when I missed her call, it went to AT&T voice mail.
When I went to retrieve her message, AT&T VM told me that my password had
"expired" and immediately required me to choose another before being
allowed to do anything else. So I changed it, retrieved her message, and
then changed it back again using the Administrative Options menu.