ORA-28221 REPLACE not specified

I'm trying to change the password of my user and I'm getting this error. The database is 9.2.0.6 Password complexity is enabled with custom function.
The description of the error is:
ORA-28221 REPLACE not specified

Cause: User is changing password but password verification function is turned on, the original password is not specified, and the user does not have the alter user system privilege.

Action: Supply the original password.

So how to change the password?

I found the right command:
SQL> alter user test_pwd identified by new_pass replace old_pass;