dpkg - restoring working packages

[Tomasz Wzietek <linuxguy@myrealbox.com>]

hello,

could someone help me figure out the following, please?

suppose i have a working package. i decide to upgrade it,
so i download the deb and use 'dpkg -i' to install it.
let's say, there are some unsatisfied dependencies that
i don't want to resolve (let's assume that it would require
some further drastic upgrading). how do i go back to the
previously working older version of the package without
reinstalling it?

from 'man dpkg':
"...(the --configure package switch) back up the old configuration
files, so that they can be restored if something goes wrong."

is there a switch or another deb-* command that would do
the trick? or do i need to download the old version and
reinstall it?

thanks for all/any replies in advance!

-- 
Tomasz