There have been quite a few occasions where I have reported a post or new topic for being low value, spam, off topic, wrong board, etc., and then became suspicious of the content and the user posting it. After a short investigation, I've then ended up reporting those posts a second time for plagiarism. Similarly, I've reported a post for plagiarism, and then gone back and reported it a second time after finding stronger evidence of plagiarism.

Disabling the "Report to moderator" function would prevent me (and others) from doing this, so I would prefer a "recall" function instead.

Alternatively, a notification somewhere on the post that I have already reported it would be nice, much like merits are displayed. This would also help when I have a few days worth of reports waiting to be handled and have to be careful not to report the same posts again.