"Reincarnations of Buddhas occur whenever conditions are
suitable and do not mean that the Buddhas themselves leave
their state in nirvana. Similarly, it is rather as reflections like
the moon on water, while the moon itself remains in the sky.
By the same simile, the moon may be reflected in many different
places at the same moment, and a Buddha may be incarnate
simultaneously in many different bodies."
(The 14th Dalai Lama of Tibet)