The ChangePassword method changes the password that will be
used to authenticate the user. This method requires that the
UserName property be set, but it is not required that the user
be logged into the POP3 server. Once the password has been changed,
the Password property will be updated with the new
password.
Note that in order to change the user's mailbox password, the
server must be running the 'poppass' service on port 106, on the same
server. Because passwords are transmitted as clear text
(unencrypted), this service is not considered secure and may not be
available.