On CentOS the timezone is controlled by /etc/localtime file.
Delete the current localtime file under /etc/ directory
# cd /etc
# rm localtime
All Europe timezones are located under under the /usr/share/zoneinfo/Europe directory as shown below.
# ls /usr/share/zoneinfo/Europe/
Amsterdam Athens Berlin Bucharest Chisinau Gibraltar Isle_of_Man Kaliningrad Lisbon Luxembourg Mariehamn Moscow Paris Riga San_Marino Simferopol Stockholm Tiraspol Vaduz Vilnius Zagreb
Andorra Belfast Bratislava Budapest Copenhagen Guernsey Istanbul Kiev Ljubljana Madrid Minsk Nicosia Podgorica Rome Sarajevo Skopje Tallinn Ulyanovsk Vatican Volgograd Zaporozhye
Astrakhan Belgrade Brussels Busingen Dublin Helsinki Jersey Kirov London Malta Monaco Oslo Prague Samara Saratov Sofia Tirane Uzhgorod Vienna Warsaw Zurich
Note: For other country timezones, browse the /usr/share/zoneinfo directory
# cd /etc
# ln -s /usr/share/zoneinfo/Europe/
Now the timezone on your Linux system is changed to Belgrade time as shown below.
# ln -s /usr/share/zoneinfo/Europe/Belgrade localtime
# date