Remove the first line and activate the second line you want to use by dialing this code**21and press the phone number of the previous line and send "#" then send it.e.g **2109090817791# then insert the previous line back. Now you can be able to recieve call with both line. Example: if you are using mtn line and you need to use it together with zain. Remove the mtn line and put the zain then dial **21*the mtn number# To cancel it: put back the authorized line then press ##21# and send it.