If you wish to move your Bitninja license from an old inactive server to a new server then please send us a ticket at https://helpcenter.bitninja.io/ticket
You can uninstall BitNinja from the old server based on this guide.
Also if you wish to move your license from one account to the other you can also do that.
Just make sure the
/var/lib/bitninja/ directories are also removed from the server, before reinstalling BitNinja from the new account.