Discussion about a Story can take place in the Comments & Attachments section of the Story dialog. The comments field supports text, markdown, emoji, files, links, and code snippets. Clicking into the comment text area will provide you with numerous helpers. 

If you happen to close a Story without saving your changes, your changes will be automatically saved. 

The system will share a message informing you of this and the Story card will have a pencil icon indicating that the Story has unsaved changes. 

Edits Not Lost Dialog

Unsaved Edits Icon

You can also react to Story comments using emoji.