How does game administrator replace inactive player?

VorlonFCW wrote:

Game host admin functions are only available in player created games, not the system generated ones as far as I know, unless they do work in system generated 22's that are not tutorial mode games.

There is only one option: to kick all inactive players and make their slots vacant. (note that inactive players are already controlled by the AI at the moment they are declared inactive)

New players may join a game in a vacant slot, providing that the game is still within the joining limits. Generally maps may not be joined after the 7 to 10 day mark (depending on map size) An exception to that is private games with a password.

In case you are in a game with these functions enabled, click on your name/flag in the upper left corner and you will find a button for administering the game.