Can you choose to have your commander deal combat damage as a regular creature to avoid commander damage tracking?

In the Commander format, the rule that a player who has been dealt 21 or more combat damage by a single commander loses the game is a mandatory tracking rule, not an optional one. There is no mechanism in the rules that lets a player choose to 'turn off' commander damage tracking for their own commander.

This tracking is governed by the Commander format rules (officially rule 903.10a in the Comprehensive Rules): 'A player that has been dealt 21 or more combat damage by the same commander over the course of the game loses the game.' The word 'dealt' here is passive and automatic — it accumulates regardless of either player's wishes.

Combat damage assignment itself follows CR 510.1–510.2, where a creature's controller assigns damage during the combat damage step. The nature of the creature as a commander does not change how damage is assigned or dealt — it simply means that damage is also tracked for the 21-damage threshold on top of reducing life totals normally.

Concretely: if your Atraxa, Praetors' Voice commander deals 7 combat damage to an opponent in three separate attacks, that opponent has taken 21 commander damage from Atraxa and loses the game — even if they still have 40 life. You cannot choose to have Atraxa 'just' deal regular damage to avoid that trigger.

The only ways to reset or avoid commander damage are effects that change which object is being tracked (e.g., if the commander changes zones and is treated as a new object, though the format rules specify accumulated damage persists — CR 903.10a explicitly states damage is tracked 'over the course of the game').