So how exactly do you change the timezone? This line of code changes your system timezone to "New York" or commonly known as "Eastern" time.
cp /usr/share/zoneinfo/America/New_York /etc/localtime

If you were thinking you want to use UTC, you'd do the following:
cp /usr/share/zoneinfo/UTC /etc/localtime

If you are looking for a different timezone, you can find them all:
ls /usr/share/zoneinfo | less

When you find the correct timezone, copy it over the localtime file. We also highly recommend keeping your time updated using NTP. To do so, run this:
yum install -y ntp ntpdate && chkconfig ntpdate on && service ntpdate start

This downloads the NTP service which will synchronize with time servers on the internet, sets the service to turn on at boot time, and starts the service.