How to delete a post
Deleting Posts from the Queue
To delete a post from your queue, hover over the post and click Delete.
Deleting Published Posts
For Twitter, Facebook, LinkedIn, Pinterest and Instagram, it is not possible to delete posts once they've been published. Once published, you would need to remove the post from the social network itself.
For Google+, it is possible to delete posts even after they've been published by visiting the "Posts" tab under "Analytics", hovering over the post you'd like to remove and clicking Delete. This will completely remove the post from your Google+ page or profile.