The following is an excerpt from an article that may help.
"If you decide to use the card for something else, or you want to trade up to a larger one, you need to do some housekeeping. The data stored on your card must be migrated back to the internal flash storage in order to avoid breaking your apps. You can do that from the internal storage menu. If you can’t fit everything, you’ll have to delete things until you’re under the limit. At that point, you can go back into the SD card storage menu and format it as “portable,” meaning it will work in other devices. If there’s any data still on it, you will lose it."
link for article:
Adoptable storage in Android 6.0: What it is, how it works | Greenbot
GRIM