Change computer -> move licence for cubase

I have a licence for Cubase AI, I have it installed on a mac and it works fine but I would like to use Cubase on my windows laptop. It says my licence has already been used so I can’t activate the software (I only get 30 days trial). I really don’t care if I can’t have cubase on my mac but I woud really need it on my laptop.

How can I get another licence activation for an other computer ? And if that’s not possible, how can I de-activate on my mac and re-activate on my laptop ?

Thanks a lot,

Ps I don’t have a USB licence thing and would like to avoid buying it …