Reinstalling a package

[Chris Stankevitz]

http://lists.freebsd.org/pipermail/freebsd-gnome/2010-June/024394.html

In the above post, a FreeBSD GNOME team member recommends "rebuilding and reinstalling sysutils/polkit, sysutils/policykit, and sysutils/consolekit".

Q: How do I "rebuild and reinstall" these applications when they were installed originally via "pkg_add -r gnome2"?

A: "pkg_add -r polkit" [fails with the message "already installed"]

Thank you,

Chris