Theoretical research has spent some years facing the problem of how to represent and provide semantics to updates of logic programs. This problem is relevant for addressing highly dynamic domains with logic programming techniques. Two of the most recent results are the definition of the refined stable and the well founded semantics for dynamic logic programs that extend stable model and well founded semantic to the dynamic case. We present here alternative, although equivalent, operational characterizations of these semantics by program transformations into normal logic programs. The transformations provide new insights on the computational complexity of these semantics, a way for better understanding the meaning of the update programs, and also a methodology for the implementation of these semantics. In this sense, the equivalence theorems in this paper constitute soundness an completeness results for the implementations of these semantics.