Samsung
Rename a Fingerprint auf Samsung
Every fingerprint you enrol on a Samsung phone gets a default label like Fingerprint 1 or Fingerprint 2. That naming comes from the biometrics system itself, not from a setting you control, so it never updates automatically even after you add more prints.
The rename option lives in the same menu where fingerprints are managed. Open Settings ➔ Biometrics and security ➔ Fingerprints, then confirm your current Pattern, PIN, or Password.
Tap the fingerprint entry you want to change, type a clearer name such as Dad or Right Thumb, and confirm with Save. The new label shows up right away in the list and in any prompt that references which print unlocked the device.
Renaming only changes the label displayed in this menu. It does not touch the actual scan data, so unlock speed and accuracy stay exactly the same.
If your goal is actually removing a fingerprint rather than relabelling it, use the delete option in the same list instead of trying to overwrite an entry with a new scan.