For the duration of this chapter of the Adventure Path, Harrow Points may be spent in the following ways:
Dexterity Rerolls: By spending a Harrow Point, you may reroll any one Initiative check, Reflex save, attack roll modified by Dexterity (i.e., a ranged attack or an attack made with Weapon Finesse), or Dexterity-based Skill check. You must abide by the new result (but if you have Harrow Points remaining, you can spend them to reroll again). This may be done after the result of the roll is known.
Dodge Bonus: You can spend one Harrow Point to gain a +1 dodge bonus to your Armor Class for the duration of the current encounter. You can spend up to 3 Harrow Points this way during a given encounter, and their effects (as with any other dodge bonuses) stack.
Speed Increase: You can also spend a Harrow Point to increase your base speed by 10 feet for one encounter. You can only spend one Harrow Point this way per encounter, however.