This is an example of some ancient royal recycling! It was dug up at Lisht North, in the pyramid complex of Amenemhat I (of Dynasty 12), but was originally created for the pyramid complex of Khufu (of Dynasty 4) at Giza (i.e. to go with the Great Pyramid).
This happened a lot throughout Ancient Egyptian history and beyond – why go to the trouble of quarrying new blocks of stone and carefully shaping them when you could just nick some from a monument of a long dead king and flip them round to carve on what had been the back side.
The female figure on this is the personification of an estate which was endowed by Khufu to supply offerings to his funerary cult in perpetuity – the text and cartouche above her head give the name of this estate: Perfect is Khufu. Khufu was not modest! 😉
It’s now in the Met Museum, acc. no.: 22.1.7
See it on my photo site: https://photos.talesfromthetwolands.org/picture.php?/1361/