According to Verizon, once you change your number, you will no longer have access to that number, but I've read posts where people escalated their issue to Tier II support and were able to get their number back. Why can't you port it over to GV? There shouldn't be any restrictions if you are the owner of the account or are granted access by the owner. What about Vonage? Not sure how long it takes to port over to Vonage, but I believe as long as the port is started prior to the number change, you should be able to keep your old number.