How to recover primal problem from its dual counterpart

I am asking this from context of optimization in machine learning. We often talk about a primal problem and how this primal problem can be solved by first converting it into a dual problem (Using Lagrange Duality concept).

However, I want to ask if opposite also holds i.e. given a dual problem formulation, is it possible to obtain its primal formulation ? What steps are required for the same ? Any resources online ?