Right now, you are only able to delete a comment that you make from the Web UI. See attached screen shot.
Would you be willing to consider adding an "Edit" button as well next to the trash can icon so users can edit their comments after they post them? This would be very handy because right now you either have to delete the comment and repost it, it make a new post with the change you want to include. I would like to see this similiar to how tools like Slack or JIRA have their edit feature set up for comments, where you select your posted comment and can select the "Edit" button to make a change.
I would grately appreciate you considering updating this feature to include this change.