It is required to factory reset the device before provisioning. Here are the instructions for how to factory reset a device. These steps use a typical Android device using a Pixel 3 running Android 9 as an example.
Step 1: Open up the Settings application, and select ‘System.’
Step 2: Select ‘Advanced’.
Step 3: Select ‘Reset’ options.
Step 4: Click on Erase all data (factory reset) option.
Step 5: Confirm your choice on the screen or screens that follow.
It can take several minutes to complete a factory reset.
Once the 'Welcome' screen is displayed, you are ready to provision your device.