LayoutHTTPHeaderOff allows you turn off any HTTPHeader directives that you may have specified. This can come into handy when you have overlapping rules. The following example illustrates this. All of the contents of the virtualhost minus the smurfdance directory will get its headers from /fullheader.cgi.
<VirtualHost www.foo.com:80>
DocumentRoot /usr/local/apache/htdocs/ LayoutHTTPHeader /fullheader.cgi <Directory /usr/local/apache/htdocs/smurfdance/>
LayoutHTTPHeaderOff
</Directory>
</VirtualHost>