Surge of Will (3.5e Feat)
From D&D Wiki
Surge of Will [General]
You are able to shrug off an effect with a mighty surge of will.
Prerequisite: None, but see description
Benefit: You get +1 on all Will saves. Once per day, you can reroll a Will saving throw after you know the outcome of the original save. On the reroll, you get to add double you base modifier, For example, if your base modifier is 5 and you have a +2 Wis modifier, your original save is at +7 (+5 +2) while your reroll would be at +12 (+5x2 +2)
Normal: You do not get to reroll a Will save.
Special: You may not have any levels in any full casting classes or PrCs. If you later gain such a level, you may retrain this feat to something in the Iron Will tree (only).