Can you redirect combat damage to a planeswalker after blockers are declared?

As of the War of the Spark rules update (April 2019), the redirection rule was removed from the game entirely. Planeswalkers are now a valid attack target chosen during the declare attackers step, just like players. There is no mechanism to redirect combat damage after blockers are declared.

Under the current rules (CR 508.1), when a player declares attackers, each attacking creature must be assigned to attack either a player, a planeswalker, or a battle that the attacking player's opponent controls. This choice is locked in at declaration time — not adjusted later.

Combat damage is then dealt to whatever the creature was declared attacking (if unblocked) or to the blocking creatures (if blocked), per CR 510.1. There is no optional redirection step at any point in combat.

Concrete example: You attack your opponent with a 3/3. You must choose at declaration time whether it is attacking your opponent directly or their Chandra, Torch of Defiance. If you chose to attack your opponent and the creature is unblocked, the 3 damage goes to your opponent — you cannot redirect it to Chandra after blockers are declared.

The old redirection rule (formerly CR 119.7) no longer exists. Any card text referencing the old redirection mechanic is updated via Oracle errata or the Comprehensive Rules to reflect the current attack-target system.