Oracle EBS API to change user password and prompt to change their password the first attempt to login to the applications

Connect to database as a apps user

Execute the below query  then it ‘ll asked  the username and password  of you want to reset

sqlplus apps/password

begin
fnd_user_pkg.updateuser(
x_user_name => '&username'
, x_owner => 'CUST'
, x_unencrypted_password => '&new_password'
, x_password_date => to_date('2','J'));
commit;
end;
/

When user  log  in to system (EBS login )  it will ask to change  password 

Password change directly   from apps user   R12.1.2   

Method 1

sqlplus apps/password

DECLARE

v_flag BOOLEAN;

BEGIN

v_flag := fnd_user_pkg.ChangePassword('USERNAME','password');

END;

COMMIT,

Method 2

In this case you will need  following password in order to change oracle R12.1.2  users passwords

Apps user password

System  password

Run apps environment variable  then run below mention command   at change as your needs

FNDCPASS apps/password  0 Y system/ password  USER username welcome