I use this method that has been working out for me so far. So you being on day 1 and talk to as many villagers as you want, and then you tt 15 days and see if anyone has a thought bubble over their head. If they do, and it's the villager you want to leave, then you talk to them. If it's not the villager you want, you go forward a day, and usually the thought bubble will go over a different villagers head. And you keep going forward 1 day, until the villager you want to leave has a thought bubble over their head.