Le 22:21 And whoever offers a sacrifice of a peace offering to the Lord, to fulfill his vow, or a freewill offering from the cattle or the sheep, it must be perfect to be accepted; there shall be no defect in it.
Fulfill your vows by doing the right thing.. not just fulfill it in a "2nd-hand" way.
Nu 30:2 If a man makes a vow to the Lord, or swears an oath to bind himself by some agreement, he shall not break his word; he shall do according to all that proceeds out of his mouth.
Everything you say must be fulfilled.
Nu 30:3 "Or if a woman makes a vow to the Lord, and binds herself by some agreement while in her father's house in her youth,
Nu 30:4 and her father hears her vow and the agreement by which she has bound herself, and her father holds his peace, then all her vows shall stand, and every agreement with which she has bound herself shall stand.
Nu 30:8 But if her husband overrules her on the day that he hears it, he shall make void her vow which she took and what she uttered with her lips, by which she bound herself, and the Lord will release her.
Nu 30:9 "Also any vow of a widow or a divorced woman, by which she has bound herself, shall stand against her.
Nu 30:13 Every vow and every binding oath to afflict her soul, her husband may confirm it, or her husband may make it void.
Above is concerning until when or how your vows shall stand or released..
De 23:21 "When you make a vow to the Lord your God, you shall not delay to pay it; for the Lord your God will surely require it of you, and it would be sin to you.