Can matza ball soup be refrozen?

Yes, matzo ball soup can be refrozen.

However, it is important to cool the soup properly before freezing it. To do this, you can place the soup in an ice bath or set it in the fridge to cool.

To reheat, let the soup sit at room temperature for several minutes until defrosted enough to easily stir. Then, simmer or microwave your cooled soup in smaller portions of a serving or so at a time for the best texture.

Keep in mind that refreezing and re-heating a bowl of soup will cause your broth to become cloudy at a minimum and at most the matzo balls to fall or get soggy with repeated temperature change, so it's wise to freeze and reheat only what you actually intend to eat and not as big quantities.