Windows 10 licensing

[Fergus Daly]

I have two Dell machines both 64 bit hardware.
One has a W10 licence from the days when the licence was free. By this I mean W10 us activated.
Even a brand new ‎installation on a brand new drive with a local ID (i.e. No Microsoft User ID) on this machine ends up activated within seconds of going online.
From this I deduce the licence is associated with some hardware attribute (motherboard?)‎. Yes?
The second machine was never activated and reports this after any new installation of W10.
Please can you tell me if it is possible to transfer the licence from the first machine to the second‎ so that it is the one that is activated? And if it is, point me to a fool's HowTo?
Thank you!

Via my BlackBerry Z10 ultraphone