 Given a class of Kripke models satisfying certain properties and a modal logic \(\L\) in the language \eqref{ML} that can reason about that class, we would like to construct a Public Announcement Logic whose soundness and completeness are straightforwardly proved. To do this, we would like to know in advance that \(\L\) is sound and complete with respect to the class of models in question, that some public announcement extension \(\LPAL\) of the language \eqref{ML} (e.g., the language \eqref{sPAL} or maybe even \eqref{PAL} itself) will include announcements that do not spoil closure, and that there is an easy way for us to determine the truth of \(\LPAL\)-formulas by looking only the underlying modal language \eqref{ML}. This way, we can “reduce” completeness of the public announcement theory to the completeness of the basic modal theory \(\L\). We call such theories for which this is possible PAL-friendly. 