HOW TO update an existing user in oracle apps

API to create Accounting Key Flexfield Concatenated Segment description in Oracle Apps R12

API: GL_FLEXFIELDS_PKG.GET_CONCAT_DESCRIPTION

• Update an existing Oracle User in R12 Oracle Apps using API -- FND_USER_PKG.UPDATEUSER
• We will try to update the email address for an existing user ‘DEMOUSER’ using the API. 
• There was no email_address populated to the user ‘DEMOUSER’ prior to running the API.

DECLARE
   v_user_name     VARCHAR2 (100)    := 'WIPUSER';
   v_email_address  VARCHAR2 (100) := 'test@WIPRO.com';

BEGIN

   fnd_user_pkg.updateuser
                           (x_user_name                    => v_user_name,
                            x_owner                        => NULL,
                            x_unencrypted_password         => NULL,
                            x_session_number               => 0,
                            x_start_date                   => NULL,
                            x_end_date                     => NULL,
                            x_last_logon_date              => NULL,
                            x_description                  => NULL,
                            x_password_date                => NULL,
                            x_password_accesses_left       => NULL,
                            x_password_lifespan_accesses   => NULL,
                            x_password_lifespan_days       => NULL,
                            x_employee_id                  => NULL,
                            x_email_address                => v_email_address,
                            x_fax                          => NULL,
                            x_customer_id                  => NULL,
                            x_supplier_id                  => NULL,
                            x_user_guid                    => NULL,
                            x_change_source                => NULL
                           );
   COMMIT;
   DBMS_OUTPUT.put_line ('User ' || v_user_name || ' is Updated successfully');
EXCEPTION
   WHEN OTHERS
   THEN
      DBMS_OUTPUT.put_line
                (   'Error encountered while updating the user and the error is '|| SQLERRM
                );
END;