For authors who wish to edit existing shares, they may do so by swiping to edit from the command center, or simply tapping the share in the wild where it was shared with anyone at any time and clicking edit from the preview.
Doing so will bring up that share in edit mode (if not deleted or still active) and allow the author to modify security factors and control settings in real time. However, they cannot edit the original share content (which his stored on thee blockchain). They may only modify access security or controls, or delete it entirely and make a new share with new copy of the content.
SWIPE TO EDIT -> MODIFY - > SAVE
Once edited and saved, authors DO NOT HAVE TO RESHARE the content. the changes take effect immediately on all copies already shard with peers. However, authors are free to re-share to new users from the share sheet link or clipboard paste as desired.