Is it permissible to divert a portion of a publicly announced donation to the mosque towards a Quran memorization circle, after obtaining the donor's approval?

Scholars have differed on the binding nature of Waqf (endowment). The majority of jurists hold that once a Waqf is issued by someone competent to act and it fulfills its conditions, it becomes binding. According to Abu Hanifa, a Waqf is permissible but not binding, and the endower may revoke it during his lifetime. In one narration from Imam Ahmad, a Waqf does not become binding except upon possession and the endower relinquishing control over it. Based on the preponderant opinion, if a person donates a sum of money to a mosque, it becomes binding upon him to spend this amount on the mosque, and he is not permitted to retract it or divert a portion of it to a Qur'an memorization circle. The entity managing the mosque must spend the entire amount on the mosque.