Get a terminal
You will want to get a terminal window open to access the linux system
Open up puTTY.
In the default (Session) category, enter the IP address and port 22. Select SSH
Find the current time in a timestamp format
You can go here to find it,
https://www.unixtimestamp.com/
You will want to copy the seconds since Jan 01 1970 from the top area.
Run the update date command
The following command will allow you to set the date on most systems.
sudo date -s @1598275106
If a system has an NTP server configured, that time will take immediate precedence after you submit the above command.
Some systems will not allow you to change the date time unless other system configuration options are changed, like the ZumIQ from Freewave.