To change timezone from command line therefore updating your date & time to a new/correct timezone, follow these steps.
Step 1: Check current datetime & current timezone
Check current datetime
date #output Fri May 24 18:45:26 +07 2019
Check current timezone
cat /etc/timezone #output Asia/Bangkok
Step 2: Update timezone to a new one
Using this command to do
sudo dpkg-reconfigure tzdata
A configure screen will display to let you choose your desire timezone
After selecting new timezone done, your datetime will be updated automatically.