Reverting packages to an earlier version

[Langdon Stevenson <langdon@xxxxxxxxxxxxxxxx>]

Just before I upgraded my fc 6.93 install to f7 approximately 124 
package updates were downloaded and installed by the package manager.

It turns out that many of them are marked:  *.fc8.i386

Since these packages have been installed many of my applications will 
not start.

Can anyone tell me how to revert these packages to an earlier version?

I would greatly appreciate any assistance

Regards,
Langdon