Pluto has been declared a planet and then subsequently reclassified multiple times. Here's a summary of the events:
Planet: Pluto was discovered in 1930 and was considered the ninth planet of our solar system for over seven decades.
Reclassification: In 2006, the International Astronomical Union (IAU) introduced a new definition of a planet, which resulted in the reclassification of Pluto. According to the new definition, a planet must meet three criteria: it must orbit the Sun, be spherical in shape, and have cleared its orbit of other debris. Since Pluto had not cleared its orbit, it was reclassified as a "dwarf planet" rather than a full-fledged planet.
So, in summary, Pluto has been declared a planet once and reclassified as a dwarf planet once.