It's very simple to retract a close vote (although doing so means you can't vote again on that post) but unless I'm missing something it's not possible to retract a re-open vote. Mistakes occur regardless of how hard we try to avoid them. In most cases these can easily be self-corrected wither via edit or retraction. I'd like to see the capability to retract a re-open vote like we have for close votes. I've reviewed Ability to retract reopen/delete votes on meta which covers this exactly and I've had some conversation in comments with @animuson regarding concerns/limitations. I hope that if you are reading this question that you'll take the time to visit Ability to retract reopen/delete votes and upvote both the Q and the A in the hope that we can get some traction on this.
Further research driven by the answers received thus far indicate that this feature has seen some interest over the years and I'm not the first to suggest it. this related bug report was closed as status-by design, which to me means this is not a bug, hence the feature request.
I agree with this. Besides correcting mistakes, there are some other situations where retracting reopen votes would be useful:
The OP rolls back an edit that changes the question or provides more information showing that the question should not really be reopened.
Someones gives a persuasive reason not to reopen. This is different from the case of a mistake--I'm talking about a deliberate reopen vote that made sense but then the voter changes their mind.
The OP asks the question to be migrated to another site, and it is high enough quality for this to make sense. Besides creating confusion, reopen votes on the question may discourage moderators from migrating it (since moderators usually have to make a decision and will usually try to abide by community consensus).
Meta discussion after the reopen vote is cast reveals a strong consensus against reopening.
The voter feels they should do something to counteract a reopen vote they've changed their mind about, so they post a comment... but the comment doesn't contribute much. It think that the ability to retract reopen votes could help prevent useless comments.
A reviewer, or any user who stumbles upon a closed post, sees it has a reopen vote that was cast by accident. So they take time to figure out if the post should be reopened, then comment to argue it should not. If the reopen vote could have been retracted, they would never have needed to take the time.
In addition, currently we can roll back edits and retract flags and (as you mentioned) close votes. The ability to retract some types of votes but not others is confusing and I am not aware of any reason for it.
For some of these same reasons, I think we ought to be able to retract delete and undelete votes.
I therefore think it's unlikely that anything will happen to it in the near future, but you can and should upvote (or bounty?) it there to indicate you want this feature.
Btw. there are similar feature requests on some other Meta sites, but all just point to the old post linked above. This is clearly a global Stack Exchange issue and not something that can be changed or resolved locally on a site.