How many times can Saran's Sabre re-roll in one combat, and can it hit both the attacker and the defender?

Question

Accepted Answer

Once per combat. The owner may force a re-roll of either the attacker's die or the defender's die, but only one forced re-roll is allowed in total. Gunpowder committed before the re-roll stays in place, and no new gunpowder can be added to the second roll.

Jamaica

How many times can Saran's Sabre re-roll in one combat, and can it hit both the attacker and the defender?