ActiveRecord::Persistence

@nzkoz Thanks. So this is where I should have been looking, and is correct:

Returns an instance of the specified klass with the attributes of the current record. This is mostly useful in relation to single-table inheritance structures where you want a subclass to appear as the superclass. This can be used along with record identification in Action Pack to allow, say, Client < Company to do something like render :partial => @client.becomes(Company) to render that instance using the companies/company partial instead of clients/client. Note: The new instance will share a link to the same attributes as the original class. So any change to the attributes in either instance will affect the other.

Full article: http://api.rubyonrails.org/classes/ActiveRecord/Persisten...