Q.when we change the container of blueberry plant , which month ?
My blueberry plant make leaves now in december , can I change the container now , it’s in small container

It is best to change containers right before new, vigorous growth starts, or when it is dormant. Many blueberries require extra care in container, as most are not suited for this purpose. You may Put it into a bigger container at almost any time though, without any negative effect. Here is an article that will help: https://www.gardeningknowhow.com/edible/fruits/blueberries/grow-blueberries-in-pots.htm