You can remove the branch and recreate it, let’s say the branch that you want to overwrite is dev:
Remove the branch in your remote host(github)
git push origin :dev
Then just push your dev again:
git push origin dev
I use Github for hosting, not familiar with unfuddle, but I think it’ll works for the unfuddle, too. 🙂
Just as @melee mentioned, you can also use
git push origin dev -f
(not sure whether the -f is valid, but --force is OK)
git push origin dev --force
to force overwrite the branch. I remember I did it before. Thanks @melee. 🙂