Obsolete ladder challenge


I have a ladder game that I initiated a while ago (late February according to game chat), but that is taking fairly long to finish. The issue is that since then, I have moved on, and the game is not relevant any more for the ladder, so I would like to free this spot to have another ladder game available.

I would rather not just resign the game, and I surely don’t mind it taking time. Ideally, I would like the game to be treated as if it wasn’t a ladder game at all.

I already PMed my opponent, offering him to fork the game and ask for a tie (assuming this is possible), but I don’t know if he is going to answer any time soon as he is in vacation, apparently.

So, can anything be reasonably done?
Here is a link to the game in question : https://online-go.com/game/4090760 .

side note: The game information tells you exactly when a game started (and ended, if so)