The Lord made some exceptions for females concerning vows, allowing her father or husband to overrule her and so her vow would not stand, but for widows or divorced women, the Lord said,
“Also any vow of a widow or a divorced woman, by which she has bound herself, shall stand against her” (Numbers 30:9).
She had to keep her vow.
That was generally how the Lord regarded vows of any kind, and in the New Testament He expects us to keep whatever we promise, and He does not make provision for exceptions.
If you make a vow, keep it.