Yes, of course you can. You can edit any of the posts you've made before.
To edit or delete, you just need to navigate to the "edit" icon in the bottom right of all of your posts.
You'll be able to edit/delete your posts from there. Alternatively, you can go to Published Posts to view all of your published posts in one place and choose which one you want to edit. In this view you can click on the word "Edit" in the lower right.
If you are a "per creation" creator and are deleting a paid post, your patrons will not be charged for it when we begin processing payments at the beginning of the following month.
Note: You will not be able to select to charge your patrons when editing a post if you have not already selected to charge.