Can you redirect commander damage to a different opponent using a replacement effect?

Commander damage is tracked by which commander dealt the damage and to which player it was dealt. Under CR 903.10a, a player who has been dealt 21 or more combat damage by a single commander over the course of the game loses the game. The key word is 'dealt to' — it tracks the actual recipient after all replacements resolve.

Replacement effects like Deflecting Palm or Boros Fury-Shield can redirect damage from one player (or permanent) to another. When combat damage is redirected to a different player using such an effect, that player does receive the damage — and crucially, it IS dealt by the commander, so it DOES count as commander damage to the new recipient (CR 614.1, 614.8).

However, this does not help the original target avoid accumulating commander damage. If you are the target of 10 commander damage and redirect it to another player, YOU took 0 commander damage this attack, but your OPPONENT now took 10 commander damage from that commander. So redirection changes WHO accumulates the damage, it does not erase or neutralize the tracking.

Concrete example: Your opponent's Zur the Enchanter (a 1/4 commander) has dealt you 18 commander damage over several turns. It swings again for 3. You cast Deflecting Palm, redirecting the 3 damage to your opponent. You do NOT reach 21 — you're still at 18. But your opponent now has 3 points of Zur commander damage tracked against them. The damage went somewhere; it wasn't negated.

So to be precise: you can use a replacement effect to redirect commander damage to someone else, changing who accumulates it — but you cannot use redirection to simply nullify commander damage tracking. The damage follows the source (the commander) to whichever player ultimately receives it (CR 614.8, 903.10a).