Themeing: Use different messages for login-update-password

Is it possible to use different messages within the login-update-password.ftl dependent on the current purpose/user workflow?

To be more precise: I want to use different captions for text phrases and button captions for the first time a user has to define his password and the following use cases (e.g. after resetting the password or changing the password on purpose).

Can this be done somehow? Thanks for any advice, kind regards