Is it permissible to change the intention of giving money from zakat to sadaqah, or vice versa?

The obligatory Zakat must be given out immediately. It is not permissible to give voluntary charity precedence over Zakat, nor is it permissible to change the intention from Zakat to charity after Zakat becomes due, unless one intends to give out Zakat immediately in place of the money given as charity. However, if the intention is changed after the Zakat has been paid to its rightful recipients, it is considered Zakat and not supererogatory charity, for the Prophet, peace and blessings be upon him, said: "Indeed, actions are by intentions, and indeed every person will have what he intended." This change of intention is considered a rejection of Zakat after one's obligation has been fulfilled. Many jurists have held that rejecting the intention after the completion of an act of worship does not invalidate it.