When a user equipment is roaming in a visited network, mid-call handover from VoWiFi to VoLTE is controlled by policies enforced in the user equipment and the home network. An inter-operator policy and a subscription policy are stored in the home network and a user equipment policy is stored in the user equipment. The roaming user equipment registers in a visited network. Later, when mid-call handover to VoLTE on the visited network is desired, and also permitted by its user equipment policy, the user equipment sends a request containing a call-specific identifier which the responsible network entity in the home network compares with the registered handover parameter having regard to the inter-operator and subscription policies. If compliance with the policies is found, then the mid-call handover is proceeded with.