Cannot delet licences on vCenter 6.0

I have installed vCenter 6.0 and some ESXi 6.0 hosts. I added licences to every host. Then I changed ip addresses on ESXi host without deleting it from inventory. Host's status was "not response". Afterwards I deleted them from inventory, but all lincences stay "used" and I cannot delete it.

How I can delete used licences?

thanks in advance