A host server is configured to switch communications associated with an account between first and second mobile devices. The server stores a mapping of the account to a first PIN which identifies the first mobile device, and communicates messages via a wireless network based on the stored mapping using the first PIN for data synchronization therebetween. The server then receives a request for device switching. In response, the server switches the mapping of the account to a second PIN which identifies a second mobile device, and communicates messages via the wireless network based on the switched stored mapping using the second PIN for data is synchronization therebetween. The mapping of the account to the first PIN may be maintained even after switching the stored mapping to the second PIN, for a subsequent request for switching back to the first mobile device for the account.