Switching Dialogue

One of the things I find myself doing often in editing is switching lines of dialogue between characters. I write the conversation one way, come back a month later and add a few more lines, often greatly increasing the depth and reach. But when I've finished adding those poignant sentences, I find myself with one character replying to himself. And it won't be easy to add in a line for the other character without messing up the flow of thought. So I just switch the lines around. Redpaw says what Crestlen was saying, and vice versa. Of course, the way they talk has to change as well, Redpaw is more blunt and simple, Crestlen more refined and articulate. So I switch a few phrases around.
Then comes the sentiments. What if Redpaw doesn't agree with what Crestlen was saying earlier? But I have found that switching sentiments oftentimes helps in the end, as you dig deeper into what each believes and how each reacts to different things.
Now, this probably wouldn't work with an old geezer and a young upstart, but with two trained hunters, it works quite well. At the same time, as I've separated Redpaw and Crestlen's characters, making them two distinct individuals, it sometimes becomes necessary to give one's lines to the other. For instance, Redpaw is more willing to forgive and move on, while Crestlen tends to muse on things, and keep them in his mind for extended periods of time. So when I find a line by Crestlen which doesn't seem to fit his character anymore, sometimes the easiest thing to do is give it to Redpaw, and see how the rest of the conversation shapes up.

They surprise me sometimes with the direction they take things.