Switching nusach

If one has always davened nusach ashkanez or sefard and then decides to daven nusach ari, can he go back to his previous nusach?

Having adopted "nusach ari" for some time (specifically, more than three times with intentions of continuing this "nusach"), a bonafide "Minhag" has set in. Considering absolute justification for the changing of one's "Minhag", (in this case, for example, a deep desire to be "in line" with the "Nusach" on one's Shule), one would have to avail oneself of the the "Hatarat Nedarim" procedure in order to change the "Minhag" (and in this case, the "Minhag of davening Nusach Ari").