(BRB) Seed of Rebirth

A model with the Regeneration special rule is permitted a special regenerate saving throw after it has failed any armour save it may have, instead of taking a ward save (if it has one). If a model has both a ward save and Regeneration, you must choose which save is used.

To take a regeneration save, roll a D6. On a 4+, or *+ if the unit has some other Regeneration(*), the wound is saved. 

Wounds caused by Flaming Attacks cannot be regenerated, and if a unit is wounded by a Flaming Attack it loses the Regeneration rule for the remainder of the phase it can be used later in the turn, though.