That would create a disaster - users have entries all over the database related to grades, enrollments, assignments, etc. etc..
If you want all your content, backup all your courses to a folder that is accessible from both moodle sites (repository of some sort works well).
Create your new site from scratch. Use the upload courses feature to create new courses and use your course backups as templates - that will bring in all the content. (Except for the front page that you will need to recreate but that shouldn't take long).