Reinstall Windows and possible licensing problem

[Leviathan 0]

Hi, I have 20 Endpoint Antivirus licenses for Windows Workstation.
I have two questions to ask: since not all licenses have been used (currently only 15/20) is there an online possibility of being able to check on which machines the license key has been activated? Since, although I have a user account provided by the distributor (of those starting with EAV-), this account and password cannot be used in any of the eset's sites.
In addition, I will have to reinstall Windows on some machines in the near future (for an active directories' change) and I will also reinstall nod32 (where it is currently already installed).
Will this process cause problems with the number of installed licenses, or is it possible to unpair the machine before formatting?
Thanks in advance.

[Marcos 5,074]

A license becomes valid as of the date of purchase, not as of the date of activation. You can control your Endpoint licenses via the EBA portal (eba.eset.com) where you can free unused seats. A seat is also freed automatically when you uninstall the ESET security product while being connected to the Internet.

[MichalJ 434]

@Leviathan as marcos has stated, you can create "ESET Business Account" and add your license there.

If the applications you are using are on the version 6 and above, after adding the license (via license key, you will have to have the license key, if you do not have it yet, you can get it via the self service function - https://eba.eset.com/LicenseConverter 

After this, you will receive confirmation e-mail to the address under which the license is registered, and after clicking the link license will be added, and all activated devices will be visible. In case you format the computers, it´s recommended to perform deactivation via EBA. If you do "standard uninstall" the license seat should be freed automatically.