My son lives in the US and got himself a new phone and has handed me his old phone. This phone was through the Verizon provider who use the CDMA network in the US. I have performed a factory reset and it works well on my home internet but I will need a nano sim which I will get today. My question is can I use or change this phone onto a GSM network. The phone is a Samsung S6 edge plus so will do my best to get it working. Thanks.....