Sometimes when addressing decisions to reopen a question I find that the OP has addressed the reason why the question was closed but still violates a condition for being open. As a common example a question was closed because it was unclear what was being asked. The question also seems to be off topic. But being unclear was the only reason given. The OP clarified the question but it was still off topic. In such a case I would vote to keep it closed. But for the benefit of the OP I would like to give my reason. I don't know of a mechanism to do this. Is there one? Should I address this as a comment in the post?
Ideally the main issues should be addressed when it is first closed (I often comment when voting to close for one reason with a brief mention that a post would close for other reasons as well -- something like "not only is this unclear, it appears to be overly broad..." etc), so that the OP is aware of the main problems to address.
My preference as a moderator when one problem it was closed for is fixed but other issues may remain is to open the post and re-close under the new reason (preferably with a comment to make the reasoning clear).
This is not always practical without a moderator (since the reopen may not succeed and even if it does the new close may not); I think a comment is a reasonable way to let the OP know that the question either may need additional editing to be on topic for our site or (if they prefer) should be flagged to migrate to a more suitable location.