Is it permissible to change the dowry after the marriage contract is written, such as if the spouses agree on an amount and then it is reduced in the contract?

We clarified the ruling on increasing the sadaq (dowry) after the marriage contract in Fatwa no. 65700. If the husband agrees to it as part of the sadaq, then it becomes binding on him. This is because jurists have explicitly stated the validity and binding nature of an increase in the sadaq by the husband after the contract, as stated by Khalil ibn Ishaq: "And an increase after the contract." Al-Kharashi explained this by saying that if the increase by the husband after the contract is intended to be part of the sadaq, then it is subject to tashattur (halving upon divorce before consummation) and has the ruling of the sadaq. However, if the husband does not agree to it, and the wife's family writes it without his knowledge and consent, then it has no اعتبار (legal weight) and is not binding on him.