How do you crop outside of the project dimensions?

I have footage that's shot in 2.7k resolution. But my project is only 1080. When I put the clip into the project I think it's auto cropped into 1080 that's great. But I want to use the extra resolution for my own cropping. Maybe there's a corner I want to focus in. Or maybe I want to use the extra resolution for stablization. How do I do that?