<p>
The only way would be for a forced screen refresh.
</p>
<p>
Powerpoint does not know about the Altet so cannot generate a refresh.
</p>
<p>
Openlp may do, but a refresh may be not what you want. If the presentation is exposing points as the sermen progresses then it may show the next point to early OR return to the start of the slide. Neither is good.
</p>
<p>
Each case will be different.
</p>