The ssgconfig menu option will also let you choose the timezone etc. If you have at least one good NTP server that the appliance can reach, and it is configured as one of the NTP server via the same wizard, time will be synched within a “short” period after this change. (Time correction should not result in “missing” time – i.e., time should be “continuous”, so if the correction is large, it may take a little while for the system to slowly correct the clock over x number of seconds). The clock will stay synched subsequently.
If the correction is huge - just use the 'date' command.