If you are trying to uninstall a RPM package from your OS, you first need to find out the package name.
To find out the package name you would need to run:
This command will display a list of packages installed on your OS.
Once, you have found the package name in-order to remove it execute this command.
rpm -e [package_name]
example: To remove webtatic package
rpm -e webtatic-release-6-9.noarch
If you want to find out whether a package is installed run this command:
yum list installed [package_name]
example: I want to find out whether webstatic is installed
yum list installed webtatic-release-6-9.noarch