COVID-19 deaths are identified using a new ICD–10 code. When COVID-19 is reported as a cause of death – or when it is listed as a “probable” or “presumed” cause — the death is coded as U07.1.This can include cases with or without laboratory confirmation.

https://www.cdc.gov/nchs/nvss/vsrr/covid19/index.htm

If c-19 deaths are being changed almost as far back as 2 years in NCHS databases and you claim it's revision…. explain why are you revising cases that far back?