Allo! I am a new Keyboard Maestro user. I have been trying out my husband’s copy to see how I like it, and have just purchased my own license after getting the email reminding me that my trial period was about to end.
However, I can’t seem to find a way to change the registered name / license. I would love to keep the macros I have already created and not start from scratch.
Advice appreciated, thanks!
– Debbie
In Keyboard Maestro, click the "Keyboard Maestro" menu then hold down the ⌥ key to get the "Deregister or Reregister Keyboard Maestro..." menu item -- reregister with your email and new licence key.
Macros aren't tied to your software registration, so there shouldn't be any problem there. But backups are always a good idea, whatever changes you are making! Even if you are running Time Machine or similar you can still make a manual backup of your macros by Quitting the Engine (bottom of Keyboard Maestro's "File" menu), Quitting Keyboard Maestro, then copying the ~/Library/Application Support/Keyboard Maestro folder.
Thanks so much for your reply, Nige. At first I couldn’t get this to work but then realized I needed to hold ⌥ key FIRST before clicking on the “Keyboard Maestro” menu. 
And thank you for the backup tips! I appreciate the info.