Conceding is the act of quitting and allowing your opponent to automatically win. In this game, we do not provide a button for a player to just quit and give all their sectors to their opponent. The opponent will still need to take all the actions to capture all of the conceding player's sectors.
If a player does not wish to play against their opponent, they can choose to not fight back and allow their opponent to freely attack them for the round. This will probably result in the attacking player capturing all of the conceding player's sectors.
A player may drop from an event at any time before or during an event, and if the chosen time is during a player's turn, the opponent will still need to manually capture the dropping player's sectors.