Since I have a multiple machine license, it sure would be nice to have a way to deactivate on one machine so it could be applied to a new machine. Making one buy a new license to replace one that's only a few months old is not very good business. Especially since there are a number of decent free progs out there. People replace machines all the time. If they can't give simple instructions to switch machines, it make you kind of wonder how good they are at coding for viruses in the first place.
The simple instructions are: Uninstall completely from 1 machine, and then install on the new machine. Your license is good for the number of machines you bought it for. As long as you only run the number you purchased, you are fine.