Responsa for Nedarim 179:3

אבל בשאלה דברי הכל אין חכם מתיר כלום אא"כ חל נדר דכתיב (במדבר ל, ג) לא יחל דברו

Said Raba: Who is so wise as to do such a thing if not R. Aha son of R. Huna, who is [indeed] a great man? For he maintains: Just as the Rabbis and R. Nathan disagree in reference to annulment, so also with respect to absolution.<span class="x" onmousemove="('comment',' V. supra 89b. R. Nathan maintains that since the vow is not yet operative, he cannot annul, whilst the Rabbis hold that he can annul it though as yet inoperative. So with reference to absolution: in R. Nathan's view, one can be absolved from his vow only when it is in effect etc. For that reason he caused him to marry first, and did not have the vow annulled immediately. ');">³</span>

Maharach Or Zarua Responsa