At the moment Sammy can only be paired with one mobile device (tablet or phone) at a time. This is a limitation of our Bluetooth bonding protocol. Otherwise anyone could connect to your Sammy and potentially disarm/arm her.
We agree it would be useful to pair Sammy with multiple devices and we are looking into this for version 1.1.
If you have paired Sammy to another phone you will have difficulty pairing her to a second phone. If you are experiencing problems pairing you can follow the reset process and then re-pair Sammy with the phone you want to use her with.