1) How to transfer the license to another domain?
You should ask for the domain change in your customer area, next to the original order details.
After you get the replay from Webdados stating that the license key is free, you should go to the plugin configurations on the new website and insert the key again.
If you cloned the website, the license key is on the database, and you need to remove it, or else this new domain will not be activated. Remove these records from the wp_options table on the new install:
Then you should be able to insert the key again and activate it on the new domain.