In some situations, the rules may allow you to re-roll a dice. This is exactly what it sounds like – pick up the dice and roll it again. You must accept the result of the re-roll, even if it is worse than the first. No single dice can be re-rolled more than once, regardless of the source of the re-roll.

If you re-roll a multiple dice roll, you must re-roll all of the dice, unless the rule granting the re-roll specifies otherwise.