Let’s open an unfinished post and send it to someone in your team to do some additional work. Let's say to a graphic designer for creating a nice artwork to this post.
Instead of clicking 'completed', click on 'assign to' and select your designer. Fill in the task what you expect him to do with the post.
This post has now been assigned to your designer to finish the artwork. You are able to see this task in your dashboard.
Graphic designers can see the list of their tasks in their interface. They download the source image, make the desired changes and upload the edited image back to the post. Once they mark this post as 'done', you will get a notification and you see this post labeled ‘done’. If you like the changes, you click on 'completed'. If you would like some additional changes, you would click on 're-assign' and repeat the process once again.