Sometimes you can't change a time zone using GUI.

For example, I don't know why, such an option is not available to me.

You can try to do it using a command line.

Open the command line as an administrator.

Use tzutil /g to check the current time zone.

Use tzutil /l to list all time zone.

Find one you want to change to and print tzutil /s "<TIME ZONE>".

For example tzutil /s "Argentina Standard Time".

Use tzutil /g to check the time zone again.