For the convenience of users, the process of installing the plugin does not require activation. Entering the license key in the plugin settings is all that is required to gain access to the plugin updates. WordPress automatically check for any updates to Permalink Manager Pro and the license validation occurs on the update server where all the requests are analyzed to prevent license abuses.
To use a "single domain" license key on a new website, all you need to do is to disable the plugin on the old website. This will prevent it from sending requests to the update server. No additional action is required, as the license validation server allow the use of the same license key on an additional third domain for a transitional period of 48 hours.
Domain names containing the words "dev", "staging", and "test" are not automatically excluded from the domain limit. However, if your development website's domain name does not include them, the "single domain" license allows you to use it on two different domains (production and development).