Introduction
The main purpose of this article is to answer the question and provide options for gaining back licenses from users that no longer actively use Confluence.
The short answer, is licenses can be freed up from by disabling users and flushing the Confluence Cache.
Disabling a User
This is currently the preferred way to get a license back. Disabling a user gives the license back so that another user may be created. There is a known bug that disabling a user will not give back the license due to the user still belonging to a group and or the cache statistics have not been flushed.
Removing a User
Before a user can be removed all edits, comments and spaces must be removed or the user will not be removed.