It wasn’t NASA tho - it was the International Astronomical Union (IAU):
NASA’s New Horizons mission made a close pass of Pluto this week. For more than 70 years, Pluto was one of nine planets recognised in our Solar System.
But in 2006, it was relegated to the status of dwarf planet by the International Astronomical Union (IAU). So why was Pluto demoted?
It wasn’t NASA tho - it was the International Astronomical Union (IAU):
https://www.bbc.com/news/science-environment-33462184