You can change the time zone for your server by using following command.

root@admin[~]#date

Wed Nov 11 19:30:29 EST 2009

For example we are changing time zone  from EST to GMT.

root@admin[~]#ln -sf /usr/share/zoneinfo/GMT /etc/localtime

root@admin[~]#date

Thu Nov 12 00:31:36 GMT 2009