Please follow the steps given below to reset your parent Unit:
Step 1. Switch off the Parent Unit by pressing and holding the “OK/POWER” button for 5 seconds
Step 2. With the Parent Unit Switched Off - Press and hold both the "MENU" and "VOLUME DOWN" buttons simultaneously (using your left hand)
Step 3. While holding the two buttons - Press and hold the “OK/POWER” button (using your right hand) until the screen displays "Model, FW version, SSID.." (hold all three buttons for around 9 seconds)
Step 4. Release those three buttons.
Step 5. Press and hold the MENU button until the screen shows “Resetting to default...” then release it
Step 6. The parent unit will reboot in a few seconds.
The Parent Unit will only show the camera that was paired in slot number 1 now.
You will need to go through the Pairing steps on the Parent Unit to add any extra cameras.