This tool lists your Hypothesis tags, and enables you to rename one or more of them.
Please do make a safe copy your annotations first. And proceed with care. There's a kind of information loss that's possible unrelated to any technical malfunction. Suppose you are using three tags, A, B, and C, to classify annotations into three buckets. Then you rename B to C. Now bucket B is gone. There is only A, unchanged. and C, which includes what was in B. You can't reverse the arrow of entropy and reconstitute the set of annotations that were in B!