A mobile device is adapted to operate in a first communication mode and a second communication mode. An identifier is acquired for a mobile device, wherein the identifier is sent to identify the mobile device when the mobile device places a call in the first communication mode. A call is placed to a destination device while the mobile device operates in the second communication mode. The same identifier is sent to the destination device while the mobile device operates in the second communication mode. The mobile device is served by a first service provider while it operates in the first communication mode. The mobile device is served by a second service provider while it operates in the second communication mode, the second service provider being different from the first service provider.