$PHP_AUTH_PW

Is there any way to change/update $PHP_AUTH_PW? Scenario: I have a site that is using basic authentication. For every page that is requested I check $PHP_AUTH_USER and $PHP_AUTH_PW against the database. That's all fine. The problem I run into is when the user changes their password. After the update to the database, I redirect them back to another page. This page then does it's authentication checking, and $PHP_AUTH_PW no longer matches what's in the database, and it prompts them for their credentials. If they enter the new password everything works fine, but I don't want them to have to re-authenticate. I don't want to use cookies, or sessions either. Chad Williamson