Fate points provide additional actions for a player and can be spent in a number of ways.
A player may spend a fate point to re-roll the last die (or one of the dice) rolled by them. This must be done right after the die is rolled and before the result of that die is used. It may be a good idea for the player to inform the GM of their intention to use a fate point if the result of the die is undesirable so the GM can provide enough time for the player to make such a decision. Note that the fate point only allows one die to be re-rolled so in the event that multiple dice are used to determine a result (such as when rolling damage or when at a disadvantage) then only one of those dice may be re-rolled by spending a fate point. The player must use the result of the re-roll even if it is lower or less desirable. This can be performed once per roll (whether an attack roll, damage roll, power check, saving throw or otherwise) performed by the player.
When using the Gather Energy action you may spend fate points to increase the amount of EP gained at a rate of 1 fate point per 1 EP.
When a player does not have the required EP to perform a desired action then they may spend fate points as if they were EP to make up the difference but only once per encounter.
Requirement for Ability
Certain abilities or actions (such as Second Wind) require fate points to perform them.