According to the texts I am still getting,. despite having already gotten a different phone, Verizon is indicating online is the best way.
Now, as to the process, and this goes for online or in a store. Refunds of the taxes and upgrade fees paid when you got the 7 are not being immediately refunded. So, if you order online or go into a store, you end up paying for the new phone, whichever version you decide upon, as though you are entering a new upgrade phase; taxes on the new phone and upgrade fees will be charged. Once the system realizes you have "upgraded," a box is sent out in order for you to ship the 7 back. Once the 7 is indicated as having been returned, any taxes and upgrade fees paid when the 7 was purchased will be refunded as a credit back to your Verizon account.
If you purchased the 7 up front at retail cost, the taxes and upgrade fees will be refunded via an account credit but the refund for the phone, allegedly, will come directly from Samsung as a refund...am guessing a check. I can't see Verizon crediting an account some $850 and I, at least, would fight it if they did. I plan on using the refund to pay the balance on the phone I switched to as an alternative.