That said, you probably want to know the way. Hmm. Well the easiest way is a copout, which is to install alternative system on some free disk space, and then copy/modify configuration files. The most obvious things I can think of are /etc/passwd (and shadow or equivalent) for user database, and fstab if there are filesystems from the old system you wish to maintain. Other configuration files will depend on the services you wish to maintain. I would think it would be better and easier to deal directly with the configuration files rather than using GUI sysadm tools.
If you really want an upgrade, you might try something rash like install the RH rpm redhat-release from the version you would like, register your system with redhat, and then do an up2date. It might work. Of course, you would still have to modify configuration files because some will be changed, and locations may be different for many I would guess (know nothing of E-smith). But it would be fun - it worked to give me a usable system to go from RH7.3 to RH9 -- though I did have to add certain rpms for usability that were "new branches" , not updates so the the up2date service did not identify the need (for example yelp - for gnome help).