The user submits the old device first, and Jingdong will arrange to pick up the old device and send it to the testing center for inspection. If there are no problems with the test, Jingdong will notify the user to ship the new device. Users in some areas can choose to choose to send the new machine in the trade-in interface at the same time as receiving the old machine, so that the trade-in process can be completed more quickly.