There's not a problem at all!
In the Autodesk console administration, unassign the licenses to the old users (if they have resigned, you can also delete them from the console), add the new users and finally assign the licenses to these new users.
You can even have several potential users in the console ready to receive the licenses at any time (more users than the licenses you have), and you can manage who receives the license and change it based on who needs a license that day, or changing the user in case of vacation, etc. (Of course, if you have more users than licenses, someone will be stuck without a license waiting for future changes).
The basic rule is, you can't replicate licenses... you can't have more people working at the same time than the number of licenses you have. Packages and the included software count as aone license, but you can change users whenever you need.
Read that, and if you have extra questions we can help.
https://www.autodesk.com/company/terms-of-use/en/general-terms
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