If you have been re-basing and picked commit(s) related to review(s) that has/have been closed (merged or abandoned) in the meantime, you can simply rebase again and instead of picking, drop the commit(s) related to the review. You should then be able to push again without any issue.
I strongly disagree with suggestions to play/modify Change-Ids.
Detailing git commands, this would give:
git fetch; git rebase origin/a_branch --interactive
Picking every commit...
Fixing conflicts and then git add ...
git rebase --continue
git push origin HEAD:refs/for/refs/heads/a_branch
-> remote rejected... change ### closed
Then do the following:
git fetch; git rebase origin/a_branch --interactive
picking (pick) every commit except those related to change ### that should be dropped (drop).
You should not have any conflict and get a rebase successfull right-away (conflicts were already solved in the previous rebase). Then:
git push origin HEAD:refs/for/refs/heads/a_branch