Change/Delete Configurations from RT Database

How does one delete/change changes on DB especially Comment Address, seting it on UI does not work, and Setting it on Configs throws an error Database Configs overwrite changes I make on RT_SiteConfig.pm:

Change of config option 'CommentAddress' at /opt/rt5/etc/RT_SiteConfig.pm line 40 has been overridden by the config setting from the database. Please remove it from /opt/rt5/etc/RT_SiteConfig.pm or from the database to avoid confusion. at /opt/rt5/sbin/../local/lib/RT/Config.pm line 2728.

What happens when you try to set it via the UI?