Transfer License from Multi Use to Single Use.

I bought one license for the Highend Theme but then a couple months later I bought a multiple license (or unlimited use license) for the same Highend theme.

I am wondering if I could just use the Unlimited License to the Single Licensed website since I already paid for it and are being charged yearly for the single license. It would save me the trouble of redoing the website with the multi-use license theme I have already bought and downloaded.

If so, how do I go about doing this? Thanks

Thank you,
Henry