On Cooking, we just noticed that using the word "hamburgers" for a tag may feel forced in cases where "burger" would sound good. However, eight years ago somebody created a tag synonym in the other direction. Now it is impossible to use a tag burger, only hamburgers. Apparently, they didn't notice the possible edge cases back then.
Is it possible now, after the fact, to somehow have the tag become burger and hamburgers be the synonym? In general, is there such functionality available to moderators or high rep users? If not, can it be fixed manually if we ask for it?