If the official ballot from your local election office arrives after you have sent in a completed Federal Write-in Absentee Ballot (FWAB), you should still use it to vote and send it in to replace the FWAB. If it arrives in time, the official ballot from your voting jurisdiction will then be the ballot counted. This is a standard procedure and does not equal voting twice.
Always return any absentee ballot sent to you regardless of when you receive it - even if it's with a note to say it arrived too late to be used, or that you did not complete it for some other reason.
A ballot sent and not returned is a sign to your local election official in your jurisdiction that you may have left your overseas address and could signal that they should take you off the voting rolls. Always return your ballots.
For November General Elections, OVF and FedEx Express offer a special ballot return program called: Express Your Vote. The program runs starting mid September. During that time, you may visit: www.overseasvotefoundation.org/ExpressYourVote for more information. Voters in approximately 95 countries will be offered free or highly discounted services for ballot return. Ballot delivery is automatically confirmed.