Switching language from French to English in Solaris 8

I have Solaris 8 OS installed in French. I have a computer with Solaris 8 OS and French language installed. This computer isn't in my office; to access it I use Exceed. I have to switch the installed language from fr_FR.UTF-8 to en_US.ISO8859-15 How can I do that? **P.S** :Even when i try to edit /etc/default/init and reboot : nothing happens.