Comment 1 for bug 1394336

This is a limitation of Gerrit, specifically that it does not actually know anything about co-authors of a change (it's just arbitrary text in a commit message from the software's perspecitve). We somewhat mitigate this problem for the "abandon" feature by also granting abandon and restore privileges on projects to core reviewers of those projects, so as a workaround you can ask anyone who has the ability to +2/-2 and approve a change to abandon or restore it for you.

Implementing any features around co-authorship would have to happen upstream in the Gerrit project, so I'm marking this won't fix from the project infrastructure perspective.