Could anybody help me with this?

I have just been asked a question, which has baffled me... Completely.

Someone I know is going over to Mac from PC, and came up with this question... "Can you just download the trial versions from Adobe, and de-authorise the PC, and straight swap the license keys?"

This one has thrown me, because it is something that I have personally never done? Would it be possible, or would it require a visit to Adobe?

Thank you for your help.