Is it permissible to reduce the amount of a vow that I made to orphans and the needy, knowing that it represents 13.7% of my salary, and after fulfilling it for two months?

Scholars disliked this type of vow, but fulfilling it is obligatory in the manner the person who made the vow specified, due to the Almighty's saying: "And let them fulfill their vows," and the Prophet's (peace be upon him) saying: "Whoever vows to obey Allah, let him obey Him; and whoever vows to disobey Him, let him not disobey Him." The vow must be fulfilled exactly as it is, without any reduction, unless the vower did not specify anything by word or intention, in which case the amount can be reduced or increased.