1. You can delete the entire map in the Navimow app. Go to: Settings>MOWER>Map Management.
Please make sure your phone is connected to the mower via Bluetooth.
2. With the firmware V1.3.5 or above, you can also adjust parts of the map in the Navimow app instead of re-creating it. Just go to Settings>MOWER>Map management>Edit, tap a boundary or off-limit island, and then tap the edit icon.
How to adjust the map: