What presentation software function allows the user to move and change the order of existing slides?

The functionality that allows a user to move and change the order of existing slides in a presentation is the slide sorter feature. The slide sorter view provides an organized layout where all slides are displayed as thumbnails, making it easier for users to navigate through their presentation. Users can click and drag slides to reorder them according to their needs, allowing for greater flexibility in structuring the presentation flow. This feature is particularly beneficial in larger presentations where rearranging slides manually in the normal editing mode could be cumbersome.

While transitions refer to the effects that occur as slides change from one to the next, and promoting a paragraph involves adjusting text within a slide, these features do not assist with managing the order of slides. The note master function pertains to the management of speaker notes associated with slides, not the reordering of slides themselves. Therefore, the slide sorter is clearly the correct choice for this function.