First--This post is based on the assumption that a staff member at the Verizon company-owned store in Billings, Montana gave me correct information -- If applicable conditions have been met a customer can, at a Verizon company-owned store, purchase a new device and trade-in an old device assuming the latter has a trade-in value.
At the aforementioned Verizon Billings, Montana location I recently purchased (on a payment plan) a (Google) Pixel 2 XL. I arrived at this location with my trade-in device--a Samsung Galaxy Note 8. In addition to said purchase I was hoping my Samsung device would be accepted for trade-in / account credit. Prior to leaving home I did the following online transactions: (1) Paid-off the remaining payments due on my Samsung device, (2) Indicated I wanted to trade-in this Samsung device. (3) Placed an order, for pick-up at this Verizon store, for a (Google) Pixel 2 XL.
When I arrived at this store the staff person who waited on me indicated that I would only be able to pick-up my Pixel 2 XL. As for my Samsung device it will be necessary for me to ship, by prepaid UPS, this device back to Verizon. This staff person indicated that my Samsung device could have been accepted by this store had I not made the mistake of doing more than just "paying-off" (online) this device. Indicating, online, that I wanted to trade-in my Samsung device was a definite mistake. Placing an (online) order for the (Google) Pixel 2 XL may, or may not, have also been a mistake.
I find myself at a loss to understand why Verizon can not simply program their computers to permit both the new device purchase, and the old device trade-in, at company-owned stores. Such a practice would be beneficial to both Verizon and the customer. The device being submitted for trade-in could be, immediately, examined for damage and any other issues that might bar a trade-in. And-The customer would realize the benefit of an expedited (trade-in) credit to his Verizon account.
As one might imagine I went the route of visiting a UPS Store for the purpose of shipping-back the Samsung device.
You placed an online order for store pickup and began the trade in process online. If you had just gone to the store to select and purchase the phone, you probably would have been able to trade in your old phone at the store.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.