Dice modification occurs during the Combat Phase of gameplay.
Players can modify dice by spending focus, evade, and target lock tokens and by resolving card abilities. Dice can be modified in the following ways:
- Add: To add a die result, place an unused die displaying the result next to the rolled dice. A die added in this way is treated as a normal die for all purposes and can be modified and canceled.
- Change: To change a die result, rotate the die so that its faceup side displays the new result.
- Reroll: To reroll a die result, pick up the die and roll it again.
- Dice can be modified by multiple effects, but a die cannot be rerolled more than once.
Adding or subtracting the number of dice that are rolled (e.g. through Jan Ors) and canceling die results (e.g. through Crack Shot) do not count as modifying dice. (FAQ, v.4.1.1, 3/15/2016)
Spending dice results is not a dice modification. (Resistance Bomber Rules Insert)
Rolling dice is different from Rerolling dice. If an effect references "rolling dice," it refers only to the first time a die is rolled, such as rolling dice during the "Roll Attack Dice" step. If an effect references "rerolling dice," it refers only to instances when dice that have already been rolled are rolled again, such as rerolling dice during the "Modify Attack Dice" step.
FFG Star Wars X-Wing Miniatures Tutorial - Dice Modifiers