How to change error message of authlogic only n certain cases

Hi all,

I update password of user and validate input data with "authlogic"
User must input current password, new password and new password
confirmation when user updates user's password.
So, I want to display follow error message if user fails to update.
"new password is invalid."

I think to edit config/en.jml
    attributes:
      user:
        password: "new password"

But, I want to display follow error message if fail to create new user
"password is invalid."
Because user input only password and password confirmation(and other
user information).

How to change error message only in the case of updating user's
password?

appreciate any help.
Thank you
Masaki.