This isn't really something you can take care of before you change computers. When you do change computers, you need to first deactivate your serial number on the old machine, then activate it on the new computer. It's normally pretty straightforward.
You mention that you are about to change computers -- please keep in mind that Panorama 5.5.2 will not run on anything newer that OS X 10.6. So if your new computer is actually new, or even anything newer than 2012, you won't be able to continue using Panorama 5.5.