"The elder to the elect lady and her children, whom I love in truth, and not only I, but also all who know the truth, because of the truth that abides in us and will be with us forever." 2 John 1
So, there is speculation about whether the lady mentioned is an actual lady or if she is a personification for the Church with her children as its members.
Relying on my only liberal belief, I'm going to say that she's an actual lady in charge of a congregation. I can't prove it. People will not be persuaded. But I think this is an example of a female elder. So sue me.
This is why I believe she is an actual lady: verse 13, "The children of your elect sister greet you." There is only one Church if I recall, so if one mentions a sister, this must mean a congregation. Again, this could mean that John is calling the intended church a woman, but then why would he say lady? He doesn't address anyone else as lady. And he seems unfazed that she serves a congregation. He only wants to give her advice about heresies in her neighborhood and how to deal with them.