When you make a mistake on your ballot, this is considered a Spoiled Ballot and you may ask for a replacement. You may receive up to two replacements or a total of three ballots.
An Overvote is when you vote for more than the number of candidates allowed in a race. If a race is overvoted, the Model DS-200 Counter will return the ballot to the voter. The voter must then return the spoiled ballot to the clerk and receive a new ballot.
An Undervote is when you do not vote in a particular race. That race will not be counted. The Model DS-200 Counter will not return the ballot to the voter unless the entire ballot is blank.