Is it permissible for a mother to revoke a gift given for the sake of Allah if she fears she may have wronged her heirs?

If a portion of a building is made an endowment (waqf) for the sake of Allah during the lifetime of the endower, this is a valid waqf and may exceed one-third (of the estate). However, if it is made after death, it takes the ruling of a bequest (wasiyya) and may not exceed one-third unless approved by the adult heirs. In both cases, it is not permissible to register the endowment in the name of one of the daughters, as this entails transferring ownership of the endowment and lacks fairness among the children. The prescribed method is to register it as an endowment for the sake of Allah, with the condition that this daughter be appointed as the supervisor (nazirah) of the endowment, overseeing it and spending its proceeds in the way of Allah.