The all the time zone files are stored in /usr/share/zoneinfo directory and its need to simlink to the /etc/localtime file to show the timezone as per your requirment.
Refer following URL to set the timezone for example we are setting GMT timezone.
admin@root#ln -sf /usr/share/zoneinfo/GMT /etc/localtime
But make sure that you are logged into Server as root to execute above command.Now check timezone has been changed or not?
admin@root # date
Tue Oct 27 03:49:53 GMT 2009
