Migrate data to adopted/adoptable storage AFTER adopting process has been finished

How do I migrate, say, /storage/emulated/0/DCIM and /storage/emulated/0/Pictures photo directories from internal to adopted storage “after the fact”, meaning after adopted storage is already set up??

After migration, I expect any program (app) to work against the new location — this I presume is the proper definition of a successful “migration”. What I don’t understand is whether migration of such common data as Pictures is supposed to take place via an app setting, i.e. in an “app-centric” fashion? What I am really looking for is a way to move the data and have all relevant apps/programs still be able to access the data without any further actions.

I have not been able to find any menu or mechanism for doing this. I have root and shell access on a moto-e4 android 7.1.1 N Nougat.