If it works fine as is Out of update period I would just turn off the WIFI connection and just use it as is. If you are intent to re-register the device, and check if it was purchased from an authorized dealer in your country that would receive the correct updates and support from people in your region instead of dealing with support overseas in China , then call Autel support in your country with the serial number and register password and ask if the registration and email account can be transferred to your name and your email address WITHOUT HAVING TO RESET the device which certainly will erase all the car apps and data and you would have to purchase a 1yr Total Care Update to re-download all the updated car software.

  There is always the chance if you obtained something cheap off E-bay that the seller is reselling something for someone else that was reported stolen even if  it was found or recovered, but insurance paid a claim, it could shows  in Autel's database as stolen and they could disable it,  so if it works out of update period , don't  fix it , and turn off the WIFI .Use your phone or laptop for the internet surfing.