RHEL how to sync network settings between GUI and configuration files in /etc/sysconfig/network-scripts/?

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http://unix.stackexchange.com – In RHEL, we can change network settings either using GUI or editing the configuration files in /etc/sysconfig/network-scripts/. I would like to know how the network settings (e.g. IP address, gateway, etc) in the configuration files are sync with the GUI and vice versa. Do I need to restart any service to sync the data? When NetworkManager is running, do I need to turn off network service? e.g. /etc/init.d/network stop? If I have edited the configuration files in /etc/sysconfig/network-scripts/, and I want to sync the new configuration with the GUI, do I need to use /etc/init.d/network rest (HowTos)