How do I change my party affiliation for voting.

In general elections you can vote for anyone regardless of your party affiliation. What party you are registered only matters in primaries - and that is only true in some states. For example, I am registered Independent in NJ. This allows me to vote in either the democratic or the republican primary - but not both. Some states only allow you to vote in your party's primary.

In many states you can change your affiliation at the DMV. If not, contact your local town or city government.

I would check your state's official website. There is usually a link to voter registration on the state website. Just follow their directions.

What State and county? Most voter registration happens at the couny level and forms are available on-line.