The Paladin ability Lay on Hands heals a friendly target for ( 10 + Paladin level ) x Charismamodifier number of hit points, or deals that much damage to an undead target.
Notes
Warforged and other characters capable of receiving Repair healing are healed a second time. The second proc is affected by Repair Amplification.
This ability does not require the paladin to be within melee (touch) range of the friend or foe being targeted, but line of sight is required.
This Paladin feat is granted at level 2, and may be used once per rest. The Extra Lay on Hands enhancements may be taken at level 1 and above to increase the number of uses per rest.
The Aasimar race also gets a similar ability, "Healing Hands", which heals ( 10 + Character level ) x Wisdommodifier. Starts with one charge per rest, optionally gains more via racial tree. Can only be used while the Bond Feat is active.
In Reaper Mode, the incoming healing will be greatly reduced by the combat self-healing penalty. To minimize the penalty, try to use Lay on Hands during periods of downtime outside of combat.