How do I uninstall or reinstall a Content pack?

Start the Launcher, then click 'Get More Content'.
Find the Content pack you wish to uninstall in the list of content packs, and click the 'Uninstall' button.
Note - if this is a mod you have created yourself, it will remove it permanently.

If you wish to reinstall that content pack, if it is a Short Fuze pack that you have a licence for, when you restart Moviestorm, the Launcher will reinstall it automatically.
If it is a mod, you would need to reinstall it from the original .addon file, as in
http://support.moviestorm.co.uk/kb/content-packs/how-do-i-install-a...