HTC One M9 User Manual page 213

If you no longer want to use your storage card as internal storage, you can
reformat the card as removable storage. Before you do so, make sure to move
all the apps and data from the card back to the phone storage. See
apps and data between the phone storage and storage card
Moving apps and data between the phone storage and storage card
If you've set up your storage card as internal storage, you can move third-party apps
that you installed and their data such as photos, media, and downloaded files to the
storage card to free up phone storage space.
If you no longer want to use your storage card as internal storage, make sure to move all
the apps and data from the card back to the phone storage.
1. From the Home screen, tap
2. Tap the name of your storage card if you're moving app data from the phone
storage to the card, or tap Phone storage if you're moving data from the
storage card back to the phone storage.
3. Tap > Migrate data.
4. Tap Move.
§ Screenshots will also be migrated.
§ When you take new photos or videos, capture new screenshots, or download
new files after the migration, they will be saved to the new storage location.
Power and storage management
> Settings > Storage & USB.
Moving
on page 213.
213