if you mean you want to migrate from Q2A to another CMS like wordpress or joomla then:
you will need to create a costum script to read your data from Q2A and import them to your new CMS. you will need a programmer familliar with both Q2A and the CMS you are migrating too.
if you mean you want to have same site(questions,users, ...) on another Q2A site(another domain) then:
duplicate(or create a copy) your Q2A database. upload and configure qa-config.php in new site to use duplicated database. in that database visit 'qa_options' table and find 'title' filed with value of "site_url" then change "content" fileds value on same row to your new website's address. that's all