Realist: You are Vadai Chayav to make new Brachos on T’fillin after going to the bathroom. That’s B’feirush in the Shulchan Aruch.
Lifting up would be an interesting Shaila to discuss. On the one hand, they are doing it because they think it’s Assur to speak with them on. Hence, it would be an Assur time to wear T’fillin and therefore a new Bracha would be required when putting them back on. On the other hand, that Halachah might only be defined by place, not time. Also, the people are wrong because it is Muttar to talk with T’fillin on. Hence, what they think shouldn’t really matter because it’s not actually an Assur time to wear T’fillin. I would think that the Halachah is that because the person knows that he may do it at the time that he puts them on and because he puts them back immediately after lifting them up (unless it’s an extended conversation, though the amount of time may not be relevant and based on a Be’ur Halachah in Hilchos Tzitzis you may have up to 2 or 3 hours with them lifted up) then he would not have to make a new Bracha after just lifting the T’fillin up.