Is it possible to adjust a post after publishing a post on Facebook through MI?

Yes, this is also possible! To do this, first, go to the 'Project messages' stream and find the post you want to edit (make use of the filters to make the search easier). Next, click on the edit icon which you will see in the following screenshot. 

Please take note: after boosting a post, it is nót possible to edit the post. You first need to stop the boosting. Now it's possible to edit the post.