The blessing over wine, בורא פרי הגפן is pronounced differently between Ashkenazim and Sefardim. Ashkenazim say hagafen; Sfardim hagefen.
There seem to be a couple possibilities for why. According to the answer on the linked previously question, Ashkenazim changed the text to be more in line with Biblical Hebrew, where at the end of a sentence, an accented segol will switch to a kamatz (simplified), while Sfardim didn't. The other possibility, ascribed to Rabbi Ovadia Yosef, is that the amen after is part of the blessing, so הגפן isn't the last word. I infer from here that he thinks it really should be hagafen, but the amen changes it.
If a Sfardi, following Rabbi Yosef's opinion, is drinking alone, with no-one around to answer amen, how should he pronounce הגפן? The way he usually does, or change it hagafen?