Here's what I wrote, less the PDF with the detailed instructions:
Do you still have the old computer, so you can run both simultaneously on a network?
In that case you can still utilize the old license by configuring the old computer as a license server for your new machine. That way you can "use up" an old time-based license until it expires. Admittedly this is a bit awkward, but it works. The new license you would then of course install on the new computer so you don't have to run two machines simultaneously.
