A process for handling downlink transmission to a User Equipment from a Service Provider, said UE being adapted to be associated with at least two Subscriber Identities,SIM, respectively associated with a first and a second communication network (1, 2), said process involving the steps of: - establishing a first connection between said UE and said first communication network; and - requesting a second connection between said UE and said second communication network further to a loss of quality of service - QoS - detected by said UE, said requesting comprising a specific value or parameter representative of a request of switching between said first and second communication network the downlink transmission from said Service Provider; - issuing from said second communication network a specific request to said Service Provider for establishing a new connection between said second communication network and the Service Provider and informing the service provider that a switching of network is requested by the UE; - transmitting an acknowledgement from said Service Provider to said second communication network confirming the establishment of the connection between the second communication network and the SP without starting data transfer through said second communication network; - transmitting from the second communication network to the User Equipment an acknowledgement related to said second communication network and said Service Provider; - issuing by said UE a request to be received by said SP and informing the latter of the sequence number of a first packet to be communicated through said second communication network instead of said first communication network; - performing data storage for said SP and said UE; - transmitting (28, 29) downlink data communication through said second communication network; - transmitting to said first communication network a request to release the connection issued by the Service Provider; - transmitting a connection release between the UE and the first communication network. - establishing a first connection between said UE and said first communication network; and - requesting a second connection between said UE and said second communication network further to a loss of quality of service - QoS - detected by said UE, said requesting comprising a specific value or parameter representative of a request of switching between said first and second communication network the downlink transmission from said Service Provider; - issuing from said second communication network a specific request to said Service Provider for establishing a new connection between said second communication network and the Service Provider and informing the service provider that a switching of network is requested by the UE; - transmitting an acknowledgement from said Service Provider to said second communication network confirming the establishment of the connection between the second communication network and the SP without starting data transfer through said second communication network; - transmitting from the second communication network to the User Equipment an acknowledgement related to said second communication network and said Service Provider; - issuing by said UE a request to be received by said SP and informing the latter of the sequence number of a first packet to be communicated through said second communication network instead of said first communication network; - performing data storage for said SP and said UE; - transmitting (28, 29) downlink data communication through said second communication network; - transmitting to said first communication network a request to release the connection issued by the Service Provider; - transmitting a connection release between the UE and the first communication network.