Following FTP steps has solved the problem.

ftp -vn $HOST <<END_SCRIPT > $LOG/delete_files.log 2>&1
quote USER username
quote PASS password
bin
prompt off
cd $PICKUP
mget *
bye
END_SCRIPT

EXIT_STATUS=$?
if [[ $EXIT_STATUS -ne 0 ]]
then
mailx -s \'"Files FTP failed'" user@xyz.com < $MSG/ftp_fail.msg
exit 1
else
mailx -s \'"Files FTP successful'" user@xyz.com < $MSG/ftp_succ.msg
fi
exit 0