Switching licenses?

I have 2 PCs, says A & B. A has a V7 license from several years ago, B has a lifetime license currently running V7 also. I would like to switch licenses between A & B, because I would like to upgrade A to V9 while I can stay with the latest V7 version on B. It is possible to do so without modifying the overall settings (the accounts for instance on each client) ?