How to Deactivate

(I apologize that this is obviously a duplicate. But I did a search saw a LONG list of posts, and can't click on ANY of them to actually read the post, does not one realize that renders the search pretty much useless)

I have a 5 license pack, and have used 3.

One really old laptop I am "de-commissioning", and have purchased a new laptop.  So I want to uninstall and free up a license before I brain wipe the drive.

On the same topic...  I also installed one license on my employers laptop, and will be retiring in a few months.  So I will want to uninstall that, and free up that one too. 

How do I free up these licenses?

Thanks in advance.