It's common as times change, so too change the hierarchies you wish to use to organize your notes. Amplenote's handling of changed tag hierarchies remains a work-in-progress as of early 2021, but we have some options already available and more planned to debut during the year.
It's currently possible to relocate a tag hierarchy through drag-and-drop:
When you drag a tag to a new location, all of the notes that had that tag assigned will have their tag updated.
A tag is considered "deleted" when no more notes refer to it. In the future we will provide batch options to delete a tag within all notes. In the meantime, the fastest way to get a tag deleted is to filter on the tag in Notes view mode, such that you can see the full list of notes that possess the tag. Then, you can click on each note and click the "X" next to the tag to remove references to the tag until they no longer exist and the tag will disappear from navigation.
Here are a couple sneak peeks at improvements in the works for later in 2021. The first is that we'll soon offer the opportunity to rename tags, merge tags, and remove it from all notes:
Design pending implementation in mid-2021
We also plan to allow sharing tags among groups of collaborators:
Your support will help fund our development of these eagerly awaited improvements. 😄