Accessing other points in shadow map from shader

In a shader you can get the shadow attenuation at the point (fragment) that you're currently at. Is it possible to get the attenuation from another point on the same object? E.g. at another UV point.

Simple example:
I have a plane with UV corners (0,0) (0,1) (1,0) (1,1). At any point/fragment I want to get the shadow attenuation from the nearest corner instead. So (0.2, 0.9) samples from the shadowmap at (0, 1).

Is this possible?