Is it permissible to change a vow from donating 10 lamps to the mosque to donating a microphone to the mosque, after 10 years have passed since the vow?

The vow must be fulfilled in the manner in which its owner vowed it, based on the Almighty’s saying: "And let them fulfill their vows," and the Prophet’s (PBUH) saying: "Whoever vows to obey Allah the Almighty, let him obey Him..." It is permissible to substitute the vow with something better, even if one is not unable to fulfill the vow in its original form. Accordingly, it is permissible to spend the mother's vowed amount on a mosque microphone if it is more beneficial than lamps.