I would never, not in any of my games, ever allow the players at the table to determine another player's alignment based on a vote or collective rule. That's not how I operate. As the GM, I would listen and observe, take opinions under advisement, but the table isn't a democracy in my world. Sometimes a few players may agree with each other and say, "Ooh! Yeah, that sounds great. We decide that Grog is now chaotic neutral."
Yeah, no, sorry, haha. That's funny but I don't. Grog remains chaotic good. Now, everyone, roll initiative.