Is it permissible to convert a plot of land bequeathed as a graveyard into a public road, given the presence of other graveyards in the village?

If no one has been buried in land endowed for a cemetery, it is permissible to exchange it for a road if there is an overriding benefit, based on the permissibility of changing the endower's condition due to need or a more apparent benefit. However, if someone has been buried in it, it is not permissible to exhume the grave and turn its place into a road, because the grave has become an endowment for its occupant.