Those of you of an older vintage may remember the flip-flop. A simple logic circuit that can be in one state or another. You get people like that too. Having no clue about anything, they tend not to have any definitive opinion of their own. Instead, they carry about with them the opinion of the last person they discussed a given subject with.
This is generally quite irritating as you can usually have two very different conversations with the same person about the same thing.
“But I thought we had agreed yesterday that the sky was blue?”
“Yes, but I had a meeting with marketing this morning and no I see that it is more of an indigo…”
Fundamentally, such people aren’t much use, but there is much to be exploited here. If these people are in decision making positions and you’d like to them to act in your favour, all you have to do is get to them last. Just make them flip to your way of thinking, make sure no one else talks to them before they enter the crucial meeting and the world is yours.