How to find the Inverse of numeric Function that was created from NDSolve

I’m a newbie to Mathematica and i do have a simple question. I have a function H that was created numerically as solution form NDSolve (like H(R)), and i’m trying to create the Inverse function R(H) for my next step of manipulation. I was trying to use InverseFunction method, but it does not seems to work since it expects a square matrix of data. any idea? Thank u E