And yet, you can indeed take your number with you when you change cell phone providers. You can convert a fixed base land line to a cell phone number, and then take it anywhere you want to, and to any cell phone provider.
I didn't really want to get into the nits of LNP, but your number is yours to take with you, not yours to sell. You also can't port it outside your local calling area, although cell carriers generally provide unlimited forwarding within their own networks. This means that, e.g., you can port your New York landline to mobile, move to California, keep the number on the same mobile carrier, but then you can't port it back to a California landline, only to a New York landline. And you can't sell the number at all.
R's, John _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf