Is it permissible to recant a vow or oath?
Question

A man swore an oath that he would not do such and such, but he wants to recant; what should he do? Should he offer expiation?
Praise be to Allah.Firstly:
Ruling on recanting an oath
If a person swears an oath and wants to recant, that is permissible if recanting does not involve doing something that is prohibited, but he must offer expiation for breaking an oath (kaffaarat yameen).
Al-Bukhaari (6718) and Muslim (1649) narrated that Abu Moosa al-Ash‘ari said: The Messenger of Allah (blessings and peace of Allah be upon him) said: “By Allah, if Allah wills, I do not swear an oath then see something better than that, but I expiate my oath and do that which is better.”
Al-Bukhaari (6622) and Muslim (1652) narrated that ‘Abd ar-Rahmaan ibn Samurah said: The Prophet (blessings and peace of Allah be upon him) said: “O ‘Abd al-Rahmaan ibn Samurah, do not seek authority, for if you are given it when you ask for it, you will be left to your own devices [without the support of Allah], but if you are given it without asking for it, you will be helped [by Allah]. If you swear to do something then see that something else is better than it, then offer expiation for your oath and do that which is better.”
Muslim (1650) narrated that Abu Hurayrah said: The Messenger of Allah (blessings and peace of Allah be upon him) said: “Whoever swears an oath then sees that something else is better than it, let him do that which is better, and offer expiation for his oath.”
An-Nawawi (may Allah have mercy on him) said in Sharh Muslim (11/108): These hadiths indicate that if someone swears an oath to do something or refrain from doing something, and breaking the oath is better than going along with it, it is recommended for him to break the oath, but he must offer expiation. There is consensus on this.
Then he mentioned the difference of scholarly opinion regarding offering expiation before breaking the oath, then he said:
They are unanimously agreed that he does not have to offer expiation before breaking the oath, and that it is permissible to delay offering expiation until after breaking the oath, and that it is not permissible to offer expiation before swearing the oath.
They differed as to whether it is permissible to do it after swearing the oath and before breaking the oath. Maalik, al-Awzaa‘i, ath-Thawri, ash-Shaafa‘i and fourteen of the Sahaabah, and several groups among the Taabi‘een regarded that as permissible, and it is the view of the majority of scholars, but they said: It is recommended (mustahabb) to do that after breaking the oath. Ash-Shaafa‘i made an exception in the case of offering expiation by fasting, as he said: It is not permissible before breaking the oath, because it is a physical act of worship, so it is not permissible to do it ahead of its time, as is also the case with prayer and the Ramadan fast. As for offering expiation by giving wealth, it is permissible to do that before breaking the oath, as it is also permissible to pay zakaah ahead of time.
One of our companions made an exception in the case of offering expiation for breaking a vow to commit sin, as he said: It is not permissible to offer expiation for that ahead of time, because that is helping in sin, but the majority are of the view that it is permissible, as in the case of vows that do not involve committing sin.
Abu Haneefah and his companions, and Ashhab al-Maaliki said: It is not permissible to offer expiation before breaking the oath in any circumstances. The evidence for the majority of scholars is the apparent meaning of these hadiths and analogy with giving zakaah ahead of time. End quote.
Secondly:
If recanting the oath involves committing a sin
If recanting the oath involves committing a sin, it is not permissible to recant, such as if a person swore: I shall not commit zina or I shall not drink alcohol. In this case, he must fulfil the oath and it is haraam to break it.
Al-Qaadi ‘Iyaad said in Ikmaal al-Mu‘allim (5/408): “then [I]  see something better than that” means something better than what he swore to do, whether that is doing something or refraining from something, that is better for his interests in this world or in the hereafter, or it is more in accordance with his inclinations and desires, so long as it is not a sin. End quote.
Breaking the oath or recanting the oath may be haraam, as in the example given above. Or breaking the oath may be obligatory, such as if someone swore not to pray or not to give zakaah, or not to uphold ties with his relatives. In that case it is obligatory to break the oath. And breaking the oath may be recommended (mandoob), disliked (makrooh) or permissible (mubaah), depending on the oath, so it may fall into one of these five categories.
In al-Iqnaa‘ (4/330), it says: Swearing an oath may be obligatory, such as if swearing the oath could save a human life, even if it is his own life, such as swearing an oath denying that he committed murder when an accusation has been made against him and he is innocent.
And swearing an oath may be recommended, as in cases when doing so serves an interest, such as reconciling between two disputing parties, or removing rancour from the heart of a Muslim towards the one who swears the oath or someone else, or warding off harm.
And swearing an oath may be permissible, such as swearing to do something permissible or to refrain from it, or swearing to confirm some news when it is true or thought most likely to be true.
And swearing an oath may be disliked (makrooh), such as swearing to do something that is disliked or to refrain from doing something that is recommended (mandoob); this category also includes swearing oaths when buying and selling.
And swearing an oath may be prohibited, such as swearing a false oath deliberately, or swearing to commit a sin or to refrain from doing an obligatory duty.
If the oath is swearing to do an obligatory action or to refrain from a prohibited action, then it is haraam to break the oath, and it must be fulfilled.
If the oath is swearing to do something that is recommended (mandoob) or to refrain from something that is disliked (makrooh), it is disliked to break the oath and it is recommended to fulfil it.
If the oath is swearing to do something that is disliked or to refrain from doing something that is recommended, then it is recommended to break the oath and it is disliked to fulfil it.
If the oath is swearing to do something that is prohibited or to refrain from doing something that is obligatory, then it is obligatory to break the oath and it is prohibited to fulfil it.
Breaking an oath to do something permissible is permissible, but fulfilling it is preferable. End quote.
But if what the questioner means by recanting an oath is that he has recanted it and decided not to fulfil it, without any consequences resulting from that, meaning that no oath has been broken, no expiation is required, and so on, that is not possible and no one says that. If that were the case, then the Prophet (blessings and peace of Allah be upon him) would have done it and would have told people about it when he explained how to recant an oath, if they saw that something else was better than it. But he did not do that; rather he advised them to break the oath, if that is better, but they must offer expiation for it.
And Allah knows best.