Changing Master Page for another

Hi

My client has inputted a lot of content into a site and decided that some of the pages need splitting into a different category which will need a new master page with associated colours etc.

Is there a way of changing the master page of a page once t's been created without having to create it again? The way you can with a template?

The page format and regions would be identical, just a few odd static changes to some of the html.

Nik