To share the control of the burglar alarm system both users needs to be member of the same home in Home + Security.
Once the first user saved the PIN ocde in Home + Security app it is possible to share the control with other member of the home.
Both users must:
1. Go to "Manage my home"
2. Enter in the room with the MyHomeServer1 device and select it
3. First user will select "Give control" showing the QR code.
4. Second user will select "Get control" and scan the QR code.
For more information check the tutorial: https://www.youtube.com/watch?v=_qEkuebND6U&list=PLlaDNT-XSIbcAbndD7ENMUMoSZXDKOm0o&index=5