Section Type Global change?

Is there any way to select multiple documents in a project and change the section type assigned to all of them at once, globally?

Yes, just select them all in the binder, outliner or corkboard, and right-click. It will be one of the functions groups along with some other metadata.

The other approach is to see whether or not this change is something procedural. For example if it is all the child items in one folder, then consider right-clicking on the folder and setting the subdocument section type default with one click. If it’s something like “all level 3 files”, then consider using Project ▸ Project Settings... in the Section Types tab, to set up a global rule.

Will that override section types already assigned?