Cherry-pick should work?
If the workflow is something like:
git checkout origin/master
make one or more commits
git push origin HEAD:refs/for/stable <-- accidentally to the wrong branch
I'm not sure that cherry-picking (locally) to master and pushing again will work because the commit at the bottom of your series is still going to have the same parent and author, and Gerrit will reject with "no changes made". Same as when you try to just push the same series of commits to the correct branch.
Cherry-picking (to a new change) on the UI might work, but you still end up with changes that you have to abandon (i.e the ones on the wrong branch).
In this situation having a "change the destination branch" feature would be very useful. There was work ongoing [1] to implement it, but it has been abandoned.