Is it possible to withdraw yourself from round robin tournaments?

I'm afraid it's not, but as some are so long and with a lot of games, I start to become quite bored with them. And to just surrender on every new game doesn't seem right.

Is it for example possible for the host to do it, or can he only do that before the tournament starts?

Good question, I am in the same situation.

Been there before !!

havent joined a round robin since! would have been nice to have had a withdrawel option

don't believe so, although I was stuck in a RR tourney with 2 other players that got booted every game... so was highly frustrating...

we almost won one game too..