Let $ R $ be a commutative noetherian ring with identity. Let $ M $ be an $ R $-module. By definition the nonfree locus $ NF(M) $ of $ M $ is defined as the set of prime ideals $ {\mathfrak p} $ of $ R$ such that $ M_{\mathfrak p} $ is a nonfree $ R_{\mathfrak p} $-module.

The question is: If $ R $ is as above and $ A$ is a noetherian $ R $-algebra, how we can modify the definition of non free locus for $ R $-algebra $A $? In other words if $ M $ is an $ A $-module, what is the meaning of $ NF(M) $?