I am troubleshooting an update-script and got stuck on the question, how
it is possible to manipulate a package, that (on upgrade) it triggers
debconf to ask me for the already set configuration once again.

IOW, I want to interactively re-debconf-igure an already installed and
configured package on upgrade, preferably triggered by the package
itsself.

Any hints and links to related documentation welcome, thanks!

Florian