MB4 248b: For What Type of Areas Does Retracting a Nullification Work? (381:1-4)

If Reuven doesn't participate in an eruv chatzerot and nullified his ownership over the chatzer, if the other residents then act on this bitul (by transferring items between their houses and the courtyard) he can't retract.

Does this work even if the other residents act on the bitul before Shabbos begins?

The residents of a chatzer can nullify their reshut to another courtyard, allowing them to carry from their houses into the other courtyard without an eruv.

Bitul reshut where a churva/ruin sits between two houses.