This study seeks to understand what motivates people to voluntarily make the switch from voting at a polling place to voting by mail. Specifically, we seek to understand whether valence appeals can convince voters to change their voting behavior. Working with the San Joaquin County (CA) Registrar of Voters, we implemented a field experiment to test four messages encouraging voters to make the switch: safety of voting by mail, cost savings for the county, social acceptance of the practice, and the added convenience of voting by mail. We find that each of the messages, except convenience, increases the likelihood that voters will switch their registration status. Interestingly, this result holds across ethnic groups.