How do I Register as a Democrat?
If you wish to change your enrollment from one party to another or from not-enrolled to a party, send a Voter Registration Form with your new choice to your county board of elections.
The board will notify you when the change takes place, by Law, after the next general election. So, unfortunately you will not be able to vote for Gary in the September primary. However, you will be able to vote for him in the general election providing he wins in the primary.