Change timezone on Redhat EL7

[root@cdh-vm ~]# timedatectl 
      Local time: Sat 2018-02-03 18:51:25 EST
  Universal time: Sat 2018-02-03 23:51:25 UTC
        RTC time: Sat 2018-02-03 23:51:22
       Time zone: America/New_York (EST, -0500)
     NTP enabled: yes
NTP synchronized: yes
 RTC in local TZ: no
      DST active: no
 Last DST change: DST ended at
                  Sun 2017-11-05 01:59:59 EDT
                  Sun 2017-11-05 01:00:00 EST
 Next DST change: DST begins (the clock jumps one hour forward) at
                  Sun 2018-03-11 01:59:59 EST
                  Sun 2018-03-11 03:00:00 EDT

[root@cdh-vm ~]# timedatectl list-timezones |grep -i singapore
Asia/Singapore

[root@cdh-vm ~]# timedatectl set-timezone Asia/Singapore

[root@cdh-vm ~]# timedatectl 
      Local time: Sun 2018-02-04 07:52:04 +08
  Universal time: Sat 2018-02-03 23:52:04 UTC
        RTC time: Sat 2018-02-03 23:52:01
       Time zone: Asia/Singapore (+08, +0800)
     NTP enabled: yes
NTP synchronized: yes
 RTC in local TZ: no
      DST active: n/a