The Phoenix sorcerer (from Unearthed Arcana: Sorcerer) gains the Phoenix Spark feature at 6th level, part of which states:
If you are reduced to 0 hit points, you can use your reaction to draw on the spark of the phoenix. You are instead reduced to 1 hit point, [...]
Would it allow the sorcerer to avoid being disintegrated by the disintegrate spell? While disintegrate turns you to ash at 0 HP, when you're reduced to 0 HP you can also use Phoenix Spark to be reduced to 1 HP instead of 0. What ends up happening?