Two logos in beamer after certain frame

Question

I am making a presentation which is devided in two parts. The first part is about experiments held in instute A and the second part is about experiments held in instute A and institute B.

Is it possible to add a second logo in a beamer presentation after a certain frame?

Let's say that this is a previous slide

This is a next slide

Answer 1

Let's reuse the code given in an answer to a similar question of yours.

Put the following into the document preamble:

\usepackage{ifthen}
\newboolean{cern}
\setboolean{cern}{false}
\logo{%
  \makebox[\paperwidth-5pt]{%
    \ifthenelse{\boolean{cern}}{%
      \includegraphics[width=1cm,keepaspectratio]{cern_logo_white.jpg}%
    }{}%
    \hfill\includegraphics[width=1cm,keepaspectratio]{ntua-logo.jpg}%
  }%
}

Before you start the first frame telling about your work done at both institutions, insert:

\setboolean{cern}{true}