Nedarim 64B

ורבא אמר: אם כן אין נדרים נשאלין לחכם.

And Rava said: It means: If so, there are no requests for the dissolution of vows to a halakhic authority. Since this type of extenuation applies to all vows, people will therefore assume that their vows are automatically dissolved, and will not take the required steps to dissolve them.

תנן: ומודין חכמים לרבי אליעזר בדבר שבינו לבין אביו ואמו, שפותחים לו בכבוד אביו ואמו. בשלמא לאביי דאמר: אם כן אין נדרים ניתרין, הכא כיון דאיחצף ליה ⁠— הא איחצף ליה.

The Talmud analyzes the dispute between Abaye and Rava: We learned in the Mishnah: And the Rabbis concede to R' Eliezer with regard to a vow concerning a matter that is between him and his father and mother, that they may broach dissolution with him by raising the issue of the honor of his father and mother. Granted, according to Abaye, who said: If so, vows are not dissolved properly, here, since he was impudent toward him by stating a vow that subjects his parent to a prohibition, he was impudent toward him and has demonstrated that he is not concerned for their honor. In such a case, there is no concern that he would pretend to regret his vow due to his parents’ honor. This is why the Rabbis concede to R' Eliezer.

אלא לרבא, דאמר: אם כן אין נדרים נשאלין לחכם, הכא אמאי פותחין? אמרי: כיון דכל נדרי לא סגיא להון דלאו חכם ⁠— הכא נמי פותחין.

But according to Rava, who said: If so, there are no requests for dissolution made to a halakhic authority, here, in the case of one whose vow involves his parents, why may they broach dissolution in this way? Why is there not a concern that people will assume that this dissolves all vows automatically? The Talmud answers: The rabbis say in response: Since it is not sufficient and applicable for all vows not to request dissolution from a halakhic authority, because the Rabbis maintain that in general, the honor of one’s parents cannot be used to broach dissolution, here too, they may broach dissolution by invoking the honor of a parent. There is no concern that this may lead one to think that vows are dissolved automatically, as this extenuation applies only to this particular vow.