With ESX it is sometimes necessary to run the command services vmware-mgmt restart should you not be able to connect with the VI client or if you need the host to re-read the esx.conf configuration file because changes you have made at the console are not visible in VirtualCenter. The services command is not available on ESXi and the supported method is to access the Direct Console User Interface (DCUI) and then to select the restart option from there as in shown in the first image.
If you have console access or have enabled SSH on your ESXi host, you can run the command /sbin/services.sh restart to accomplish the same thing as is shown in the second image. This will restart the agents that are installed in /etc/init.d/ and with a default install that includes: hostd, ntpd, sfcbd, sfcbd-watchdog, slpd and wsmand. It will aalso restart the VMware HA agent (AAM) if that has been enabled on the host.