From Monarchists.Wiki

Vashti was a queen consort of King Ahasuerus of Persia. During a feast, Ahasuerus was in high spirits due to wine and commanded Vashti to put on her crown and display her beauty to his guest, but she refused. The king became enraged and asked his advisors Carshena, Shethar, Admatha, Tarshish, Meres, Marsena, and Memucan for advice. Memucan then explained that Vashti wronged the king and his noble subjects and that Vashi's behavior would set a bad example that women might follow.

Vashti the queen has not only wronged the king but [also] all the officials (royal representatives) and all the peoples who are in all the provinces of King Ahasuerus. For the queen’s conduct will become known to all women, causing them to look on their husbands with contempt (disrespect), since they will say, King Ahasuerus commanded Queen Vashti to be brought before him, but she did not come. This [very] day the ladies of Persia and Media who have heard of the queen’s refusal will speak [in the same way] to all the king’s officials, and there will be plenty of contempt and anger.

— Esther 1:16–1:18 (AMP)

Memucan then suggested punishing Vashti by demoting her and selecting a new wife to serve as queen consort.

If it pleases the king, let a royal command be issued by him and let it be written in the laws of the Persians and Medes so that it cannot be repealed or modified, that Vashti is no longer to come before King Ahasuerus; and let the king give her royal position to another who is better and more worthy than she. So when the king’s great decree is proclaimed throughout his [extensive] kingdom, all women will give honor to their husbands, from the great to the insignificant.

— Esther 1:19–1:20 (AMP)

Ahasuerus and his noble officers found Memucan's advice good, so Ahasuerus demoted Vashti and issued an edict affirming the role of husband in a household. Ahasuerus then sought out a new queen consort, and this new queen consort would be Esther.