A personal example of this. A company I was working for made a lot of people redundant, although they wanted to retain me. I wasn't happy with the situation, not least because I would end up shouldering a lot more work in the reduced team. I knew I could find work somewhere else at least on what I was getting (with less responsibility). So I asked for a raise to retain me.

They refused, and I resigned immediately. I found a much better role, on more money, with better career opportunities quite quickly. My BATNA meant I could ask for the raise with some confidence. Of course you have to be willing to follow through; I wasn't bluffing.