When a villager is in boxes (the day before they go void) invite another player with less then 10 villager and let them talk to the villager in boxes. Then they will say something like "its all good, Im moving to ____ with ___" and thats it:3 did I explain it well?^~^
Or I *think* if you void someone and then someone visits you within a day or two, they'll get that villager. what I accidentally did to my friend, I'm so sorry