When you reject a site or a provider, you often want to add a quick note with the reason. Instead of sending an email yourself (and needing to look up the provider's email address in the process) you can also use the workflow to do it for you. In the workflow menu dropdown, use the "advanced" option. 

• Select the right workflow transition that you want.
• Add a comment.
• Hit "submit.

The result is that your comment is send to the content author. Works like a charm.