Take away a neder

Question

Is it possible to remove a neder through saying kol nidre alone on a regular weekday? And if not, what possibilities are there to remove a neder without asking a Beit din.

Answer 1

1. Removing a neder is called unraveling or cancellation (התרה).
2. The link between Kol nidre and removing neder needs to be explained.

See Mishna Nedarim 3, 1 with its paraphrase in Gemara summarized in Bartenura:

רַבִּי אֱלִיעֶזֶר בֶּן יַעֲקֹב אוֹמֵר, אַף הָרוֹצֶה לְהַדִּיר אֶת חֲבֵרוֹ שֶׁיֹּאכַל אֶצְלוֹ, אוֹמֵר, כָּל נֶדֶר שֶׁאֲנִי עָתִיד לִדֹּר הוּא בָטֵל, וּבִלְבַד שֶׁיְּהֵא זָכוּר בִּשְׁעַת הַנֶּדֶר:‏

Rabbi Eliezer Ben Jacob said: also he who wishes to subject his friend to a vow to eat with him, should declare: every vow which i may make in the future shall be null'. [his vows are then invalid,] providing that he remembers this at the time of the vow.

מְפָרֵשׁ בַּגְּמָרָא דְּחַסּוֹרֵי מִחַסְּרָא וְהָכִי קָתָנֵי, הָרוֹצֶה שֶׁיֹּאכַל חֲבֵרוֹ אֶצְלוֹ וּמְסָרֵב בּוֹ וּמַדִּירוֹ , נִדְרֵי זֵרוּזִין הוּא. וְהָרוֹצֶה שֶׁלֹּא יִתְקַיְּמוּ נְדָרָיו כָּל הַשָּׁנָה יַעֲמֹד בְּרֹאשׁ הַשָּׁנָה, וְיֹאמַר, כָּל נֶדֶר שֶׁאֲנִי עָתִיד לִדֹּר יְהֵא בָטֵל. וְיַעֲמֹד בְּרֹאשׁ הַשָּׁנָה לָאו דַּוְקָא, אֶלָּא הוּא הַדִּין בְּכָל עֵת שֶׁיִּרְצֶה וּלְכָל זְמַן שֶׁיִּקְבַּע:‏

The text is defective, and this is what was taught : He who desires his friend to eat with him, and after urging him, imposes a vow upon him, it is 'a vow of incitement [and hence invalid].

and he who desires that none of his vows made during the year shall be valid, let him stand at the beginning of the year and declare, 'Every vow which I may make in the future shall be null.

Rambam Hilchot Nedarim 2, 5: If he remembered the stipulation at the time he made the vow, the vow is effective, for by taking the vow, he nullified the stipulation. If, however, he did not remember the stipulation until after he made the vow, the vow is nullified even if [immediately after taking the vow], he brought the stipulation to mind and maintained it. Although he did not verbalize his retraction at the time [he made the vow], the retraction preceded the vow and he verbalized it beforehand. There is an authority who rules stringently and says that he must remember the stipulation immediately thereafter taking the vow.

1. We see that this is, according to the Bartenura, an option to cancel in advance a neder. This is not linked to an already existant neder. It is necessary to remember this prior condition at time of the future neder, and to agree with it. Following this explanation, the mention of Nedarim, this mishna is probably talking about Kol Nidre. In Kol Nidrey is oriented to future Nedarim. A man can make a kind of Kol nidre alone and for 10 coming years, not one only.
2. So Rabenu Tam decided, according to this that in Kol nidrey we say Miyom kipurim ze Leyom Kipurim haba... and not Miyom kippurim Sheavar Leyom Kippurim ze
3. According to the Nussach Myom Kippurim Sheavar (which are accredited by the Rosh despite Rabenu Tam, and seems to be the original nussach of Baale Hatosfot before the modifications of Rabenu Tam), however, Kol nidrey is an annulation but only for already existant nedarim, but for "Shigegat Tsibur" (a kind of Collective erroneous neder) See Bet Yossef OC 619. An other point: In this kind of Kol Nidre there is 3 men that play the role of Dayanim to cancel the neder. Kol Nidrey is not made to be said by a "Yachid".
4. Anyway for a Yachid, the Halacha is more stringent and the annulation must be with a bet din and the noder must explain to the chacham the neder in way to obtain an annulation. See SA YD 212, 2-3 and see SA OC 619, 1
5. Without asking a Bet Din or a Chacham, I do not know how to remove a Neder.