HOW TO CHANGE A SYSTEM LOCALE To en_US in solaris 10?

SOLUTION:
#locale
LANG=
LC_CTYPE="C"
LC_NUMERIC="C"
LC_TIME="C"
LC_COLLATE="C"
LC_MONETARY="C"
LC_MESSAGES="C"
LC_ALL=

#more /etc/default/init

# Copyright 1992, 1999-2002 Sun Microsystems, Inc.  All rights reserved.

# Use is subject to license terms.
#
#ident  "@(#)init.dfl   1.7     02/12/03 SMI"
#
# This file is /etc/default/init.  /etc/TIMEZONE is a symlink to this file.
# This file looks like a shell script, but it is not.  To maintain

# compatibility with old versions of /etc/TIMEZONE, some shell construc

# (i.e., export commands) are allowed in this file, but are ignored.
# Lines of this file should be of the form VAR=value, where VAR is one of
# TZ, LANG, CMASK, or any of the LC_* environment variables.  value may
# be enclosed in double quotes (") or single quotes (').

TZ=Asia/Calcutta
CMASK=022

===>To add locale en_US

#localeadm -a en_US.ISO8859-15  -d  /mnt/S10U6_OS/Solaris_10/Product/
[test1@root:/]#locale
LANG=
LC_CTYPE="C"
LC_NUMERIC="C"
LC_TIME="C"
LC_COLLATE="C"
LC_MONETARY="C"
LC_MESSAGES="C"
LC_ALL=

[test1@root:/]#locale -a
C
POSIX
en_CA
en_CA.ISO8859-1
en_CA.UTF-8
en_US
en_US.ISO8859-1
en_US.ISO8859-15
en_US.ISO8859-15@euro
en_US.UTF-8
es
es.UTF-8
es_MX
es_MX.ISO8859-1
es_MX.UTF-8
fr
fr.UTF-8
fr_CA
fr_CA.ISO8859-1
fr_CA.UTF-8
iso_8859_1