In some situations, the rules allow you a 're-roll' of the dice. This is exactly as it sounds - pick up the dice you wish to re-roll and roll them again. The second score counts with a re-roll, even if it means a worse result than the first, and no single dice can be re-rolled more than once, regardless of the source of the re-roll.
Re-Rolls
Source: 3rd-A-Palooza (3.5) Rulebook v1.4, p. 1