You can edit presentations and respond to comments in Slack (channels or individuals) using Show's Notify Collaborators. 

To notify collaborators from Show:

1. Open the required presentation in Show.
   
   
   
   
   
   
2. Click the Notify icon on the top-right corner. All the shared channels and members display in the window. 
   
   
   
   
3. Enter your message and click Notify. The message will be delivered to the collaborators.