up2date has no dist-upgrade

With Debian/Ubuntu you can "apt-get dist-upgrade" but I know of no equivalent in RedHat. According to the RHEL5 release notes, you may "perform an upgrade from the latest updated version of Red Hat Enterprise Linux 4 to Red Hat Enterprise Linux 5". But they don't say how. MIT has some instructions which propose either having the installer upgrade or doing a fresh install. There also seem to be some yum issues after the upgrade.