You only need to pair your phone with the S1 once. Once you have paired your phone with the S1 they will reconnect to each other in future without you having to repeat the pairing process. If you need to pair an additional phone, simply:
The S1 can store pairing information for up to 8 Bluetooth devices. If you pair a ninth device, it will replace the stored pairing information for the phone that has not connected to the S1 for the longest time.
You can connect the S1 to two phones at the same time. For more information, see Using More Than One Phone At The Same Time (Multipoint).