Board Game Arena

Thanks for your answer ! I use the small white flag to concede, but this requires the agreement of my opponent each time, who may refuse.

When I am about to lose a game and click on 'concede', my opponent can refuse and I have to stay in the game. But when my opponent loses, they can concede victory and the game ends without me being able to refuse the concession. Why is there this difference? Thanks for your explanation !