All you need to do to reserve a name is to log in to the game, start creating a new character, and then follow the prompts from there. An extra character slot will be added to the game when the Paragon launches, but if you already have the maximum number of characters on a server, you will have to delete one to reserve your name. The name is also coming with a built-in expiration, as it remains reserved on the server for one month after the Paragon goes live. Still, at least this way you won’t be resorting to the dolphin sound approach.
Source: Official Site