Praise be to Allah.
If a person vows to do something and does not do it, then he has to offer kafaarat al-yameen (expiation for not fulfilling a vow). For example, if he says, “By Allaah, I will speak to So and so” or “By Allaah, I will visit him” or “By Allaah I will pray such and such”, and so on, then he does not do what he vowed to do, in this case he has to offer kafaarat al-yameen, if he was of sound mind and knew what he was saying. But if his anger was so intense that he was not really aware, then the vow is not binding, because it is essential that he is aware of what he is saying. So if his anger was so intense that it made him unaware of what he was saying, and he was out of control, then in this case he does not have to offer kafaarah, like one who is insane, feeble-minded or asleep.
He can forego doing what he vowed to do, if he thinks that that is in his best interests, and he can offer expiation for his vow, because the Prophet (peace and blessings of Allaah be upon him) said: “If you make a vow, then you see that doing something else is better than that, offer expiation for your vow and do that which is better.” (Saheeh – agreed upon).
So if he vowed not to visit someone, then he sees that it is better to visit him, he should visit him and offer expiation for his vow, and so on.
It does not matter whether he offers the expiation before or after doing the alternative action.
And Allaah is the sources of strength.