When git is constantly asking you to type your password, make sure to do this.
Here the details:
eval $(ssh-agent) <- start the ssh agent.
ssh-add <- you add your private key to it. Follow the steps here.
ssh-add -K <- Save key permanently.
git remote add upstream [git@github.com:[user]/[repo].git
git remote add [user] git@github.com:[user]/repo.git
Inside the branch that you want to change the name run this:
git branch -m new_branch
Then delete the old branch:
git push origin :old_branch
Push the new branch, set local branch to track the new remote
git push --set-upstream origin new_branch