Once in a while (yet often enough) it happens that I have to change an already pushed git tag. Usually because I violated my own naming scheme.
Yet I also somehow can’t keep the necesserry commands in mind:
git tag newTag oldTag git tag -d oldTag git push origin :refs/tags/oldTag
Basically it is just: copy/link newTag to oldTag, remove oldTag, delete remote oldTag.
Also see the git man page for further parameters.