A method (100, 110, 120) performed by a server of switching a voice communication at a wireless device from a first call leg established on a first communication network of a first type to a call leg established on a second communication network of a second type, the wireless device being associated with a telephone extension of an enterprise communication network and communicating with a second device, said method (100, 110, 120) comprising: maintaining (100a, 100b, 110a, 110b, 120a, 120b) the first call leg to the wireless device and a second call leg to the second device; receiving (100c, 110c, 120c) information from the wireless device indicating that the second communication network is available to switch the voice communication at the wireless device to the second communication network; establishing (100d, 11 0e, 120e) a third call leg to the wireless device using the second communication network; bridging (100e, 110f, 120f) the first, second and third call legs together using a muted bridge connection whereby the third call leg is initially muted; determining whether to switch the voice communication at the wireless device to the second communication network; wherein the received information includes information that a quality of service of the voice communication over the first communication network is below a first threshold and a signal strength of the voice communication over the first communication network is below a second threshold, and wherein the determining act determines to switch the voice communication at the wireless device to the second communication network if the quality of service remained below the first threshold and the signal strength remained below the second threshold for a predetermined period of time; and if it is determined to switch the voice communication at the wireless device to the second communication network, dropping (100f, 120h) the first call leg and unmuting (100g, 120i) the third call leg; otherwise dropping the third call leg without having un-muted the third call leg. maintaining (100a, 100b, 110a, 110b, 120a, 120b) the first call leg to the wireless device and a second call leg to the second device; receiving (100c, 110c, 120c) information from the wireless device indicating that the second communication network is available to switch the voice communication at the wireless device to the second communication network; establishing (100d, 11 0e, 120e) a third call leg to the wireless device using the second communication network; bridging (100e, 110f, 120f) the first, second and third call legs together using a muted bridge connection whereby the third call leg is initially muted; determining whether to switch the voice communication at the wireless device to the second communication network; wherein the received information includes information that a quality of service of the voice communication over the first communication network is below a first threshold and a signal strength of the voice communication over the first communication network is below a second threshold, and wherein the determining act determines to switch the voice communication at the wireless device to the second communication network if the quality of service remained below the first threshold and the signal strength remained below the second threshold for a predetermined period of time; and if it is determined to switch the voice communication at the wireless device to the second communication network, dropping (100f, 120h) the first call leg and unmuting (100g, 120i) the third call leg; otherwise dropping the third call leg without having un-muted the third call leg.