What happens to the plates?
Off before they take possession — then turn them in
The seller should remove the plates before allowing the buyer to take possession. You may move them to a replacement vehicle; if you are not doing that, turn them in or inactivate them online, at a DMV customer service center, or at a DMV Select. And collect your money: with six months or more left in the registration period you may qualify for a refund — file an Application for Vehicle Registration Refund (FMS-210) and mail it with the plates, or return them in person. Partial refunds exclude one-time plate reservation fees, Road Tax for heavy trucks and any late fees.
Source: Virginia DMV, Buying/Selling a Vehicle — remove license plates