2,668. Permitting an Oath Isn't Judgment

Hilchos Shevuos 6:6

Relatives may permit one's vows and oaths. Oaths and vows can be permitted at night and standing because permitting an oath or a vow isn't a form of judgment. Since it's not judgment, one may seek to have an oath or a vow permitted on Shabbos if doing so is necessary for Shabbos. An example would be permitting an oath that prevents one from eating and drinking on that day. Even if he could have had his oath or vow permitted before Shabbos, he may still do so on Shabbos because doing so is necessary for Shabbos.

Hilchos Shevuos 6:7

Let’s say that Reuven imposes an oath on Shimon and Shimon answers amen or accepts the oath. If Shimon later regrets it and seeks to have the oath permitted, it may only be permitted in Reuven’s presence. Similarly, if Reuven takes an oath or a vow not to benefit from Shimon, or prohibiting Shimon to benefit from him, and he changes his mind and seeks release from a Torah scholar, the oath or vow is only permitted in Shimon’s presence. This is the case even if Shimon was a minor or a non-Jew so that the one who was affected will know that the vow or oath was permitted and he can benefit from him.