I’ve never had to do that so I think TN is a closed primary state.
What I find indicates TN is a open primary state. Not sure of exactly how it works.
In Texas one didn’t register by party and selected the party ballot in which you
wanted to vote when you went to the polls on primary day. So I was wondering how
it worked in TN. Thanks for your response.
http://ballotpedia.org/Voting_in_Tennessee
https://www.google.com/#q=tennessee+open+or+closed+primary