From the SRD:
Second Chance
Clairsentience
Level: Seer 5
Display: Mental
Manifesting Time: 1 standard action
Range: Personal
Target: You
Duration: 1 round/level or until discharged
Power Points: 9
You take a hand in influencing the probable outcomes of your immediate environment. You see the many alternative branches that reality could take in the next few seconds, and with this foreknowledge you gain the ability to reroll one attack roll, one saving throw, one ability check, or one skill check each round. You must take the result of the reroll, even if it’s worse than the original roll. You do not have to make another roll if satisfied with your original roll.
Fate of One
Clairsentience
Level: Seer 7
Display: Mental and visual
Manifesting Time: 1 immediate action
Range: Personal
Target: You
Duration: Instantaneous
Power Points: 13
Your limited omniscience allows you to reroll a saving throw, attack roll, or skill check. Whatever the result of the reroll, you must use it even if it is worse than the original roll.
You can manifest this power instantly, quickly enough to gain its benefits in an emergency. Manifesting this power is an immediate action. If you use the power to reroll a saving throw, you can manifest this power even when it is not your turn.