If you're currently on the branch you want to rename:
git branch -m new_name
Or else:
git branch -m old_name new_name
You can check with:
git branch -a
As you can see, only the local name changed Now, to change the name also in the remote you must do:
git push origin :old_name
This removes the branch, then upload it with the new name:
git push origin new_name