Microsoft today updated Network+ Settings app in Windows Phone Store to v188.8.131.52. This update allows you to edit your call settings when in 4G.
– Edit your call settings when in 4G
Network+ gives you additional call waiting and call forwarding settings. If you have a dual SIM phone, you can also use Smart Dual SIM to set up forwarding between SIMs and never miss another call. The latest version of the Network app can be downloaded here.