If you want to set the camera to overwrite the old files when the SD is full on your phone, check the guides below.
Applies to: All Reolink cameras except Argus 2, Argus Eco, Argus Pro, Argus PT, Argus 2E, Reolink GO, Reolink GO PT, and add-on cameras like B400, B800, D400, D800, B500, D500. B1200, D1200
Step 1. Go to Device Settings > Camera Recording, and then enable Camera Recording.
Step 2. Enable Overwrite.