A user entity (UE) such as a smartphone is configured to connect to both Wi-Fi and a Long Term Evolution (LTE) cellular network for voice and data services. For voice, the UE supports both Voice over LTE (VoLTE) and Voice over Wi-Fi (VoWiFi). When the UE is connected to VoWiFi and roaming from a first Wi-Fi access point to a second Wi-Fi access point, the UE and Mobility Management Entity in the cellular network carry out a preparatory handover to VoLTE to prevent service loss in the event of an unsuccessful VoWiFi connection from the second Wi-Fi access point.