LB – I’ve mentioned this in the past, but I’ll repeat it here. I know an Ashkenazi man who married a Sephardi woman. He wanted to take on her minhagim, so he asked Rav Ovadiah zatsal who said that he is allowed to do so. In that case, it seems to have been because Rav Ovadiah zatsal supposedly held that really everyone in Eretz Yisrael is supposed to be following Sephardi minhagim. (although l’maaseh, in his piskei halacha, he does posken that Ashkenazim can follow the Ashknazi psakim, so it doesn’t sound like he literally thought that every Ashkenazi in E”Y MUST become Sephardi).
please note: I wrote the word “supposedly” because it is second-hand information from one person, so I can not verify the accuracy of the statement.