I'm planning on purchasing an iPhone 13 Pro. I'd prefer to purchase it from Best Buy in-person. I see from Best Buy that I can still use Verizon Payments and also take advantage of the trade-in on my iphone X 256GB. I'm on an old 24GB plan, so I'll have to switch to the new Get More Unlimited. Do I buy the phone at the Best Buy store then follow up with Verizon - for both turning in my old phone and changing my plan, or do I have to change the plan before the purchase?